Next Level Performance
May 13, 2026 • 11 min read
The Kia Stinger GT 3.3 twin-turbo was the dark-horse sport sedan of its era — 365 hp, 376 lb-ft of torque, rear-wheel-drive bias, and a chassis tuned in Germany. The one thing it never quite nailed from the factory was the soundtrack. The OEM mufflers use 1-7/8" tubing that has been physically crushed to clear the rear axles, which is exactly the kind of restriction that makes a cat-back exhaust worth the money on a forced-induction car. If you own a 2018-2023 Stinger GT and you have been Googling the best cat-back exhaust options, this guide compares every system we stock at our Tampa, FL shop, with real specs, honest drone notes, and what the 2022 active-valve refresh changed.
Our Verdict
For most 2018-2023 Stinger GT 3.3T owners, the Borla S-Type is the right answer — just pick the part number that matches your year.
Borla’s S-Type Cat-Back nails the dual-personality the Stinger deserves: deep and aggressive under load, civil at cruise, and engineered to keep your factory active-valve system fully functional on the 2022-2023 refresh cars. If you want even less highway drone or you have already added downpipes, MagnaFlow’s 2.5" Competition system is the smarter pick.
Shop Our Top Pick →Why the Kia Stinger GT 3.3T Actually Needs a Cat-Back
Cat-back exhaust gains on a naturally-aspirated V6 are usually overstated. On the twin-turbo Lambda II 3.3L in the Stinger GT, the story is different. Kia engineers fed two turbochargers into a pair of mufflers using crushed 1-7/8" tubing routed around the rear axles — an OEM packaging decision, not a performance one. Forum dyno reports from MAPerformance and Stinger Forum members consistently show measurable flow gains from cat-back upgrades alone, before any downpipe work. Realistic numbers fall in the 5 to 15 wheel horsepower range with no tune. The bigger win is sound character: you finally hear the 3.3 twin-turbo working.
There is one curveball you need to plan around. The 2022 model-year refresh added a factory active-valve exhaust that opens in Sport mode and closes in Comfort and Eco. That valve is the reason Borla offers two different part numbers — one for 2018-2021 cars without the valve, and one for 2022-2023 cars with the integrated actuator. Bolt the wrong system to the wrong year and either you lose the valve functionality entirely or it never opens at all. We’ll walk through both below.
Borla’s S-Type system uses 2.25" T-304 stainless tubing with a Merge X-Pipe and Polyphonic Harmonizer mufflers.
Top Pick for 2022-2023 Stinger GT: Borla S-Type with Active Valve
If you have a 2022 or 2023 Stinger GT, this is the only cat-back we stock that preserves the factory active-valve system. The integrated actuator hardware plugs straight into the OEM connector, the valve opens in Sport mode exactly like stock, and the exhaust note shifts from quiet cruiser to deep V6 growl on command. It uses the same T-304 stainless, 2.25" True Dual piping, Merge X-Pipe, and Polyphonic Harmonizer architecture as the older system — just with the valve hardware bolted in.
What We Like
- + Only major-brand cat-back that retains full factory active-valve functionality on the 2022-2023 refresh cars.
- + Dual-personality character: civil in Comfort and Eco, noticeably more aggressive when the valve opens in Sport mode.
- + Same proven T-304 stainless, Merge X-Pipe, and Polyphonic Harmonizer architecture as the legacy 2018-2021 system.
Things to Consider
- – Roughly $500 more than the 2018-2021 version — you are paying for the valve hardware.
- – Owners say the valve-open vs. valve-closed delta is real but subtler than a full straight-pipe swap.
Key Specifications
Best for 2018-2021 Stinger GT: Borla S-Type (the Original)
For pre-refresh cars, this is the cat-back our Tampa shop has installed more than any other on the Stinger platform. The 140736 part predates the 2022 active-valve system, so it is a straight true-dual 2.25" T-304 system from cats to tips. The Polyphonic Harmonizer mufflers use multi-diameter, multi-length tuned chambers that give the Stinger its trademark Borla character — deep, layered, and noticeably more aggressive than stock without crossing into ricey territory. Bolt-on, no welding, reuses factory hangers and rear-fascia tips.
What We Like
- + Deep, harmonized polyphonic tone that suits the Stinger’s character — significantly more aggressive than stock without sounding cheap.
- + Premium T-304 stainless construction with Borla’s lifetime-of-vehicle warranty — one of the best in the cat-back business.
- + True bolt-on with no welding, factory hangers reused, no tune required — ECU sees no change downstream of the O2 sensors.
Things to Consider
- – Owners consistently report mild drone in the 1,500-2,200 rpm cruising band — not deal-breaking, but Borla’s “drone-free” marketing is optimistic.
- – Does not include exhaust tips — you reuse the factory valance tips or add the Borla carbon fiber tip kit covered below.
Borla’s multi-chamber, multi-diameter Polyphonic Harmonizer mufflers shape the S-Type tone.
Best for Daily Drivers and Tuned Cars: MagnaFlow Performance Cat-Back
If you commute long highway miles or you have already added downpipes and are eyeing a tune, the MagnaFlow 19406 is the smarter pick. It steps up to 2.5" mandrel-bent stainless piping — a quarter-inch larger than either Borla — with six straight-through tuned-chamber mufflers and a quad split rear exit. The result on highway-speed drives is two things at once: deeper, more open WOT tone with noticeably less drone at the 1,500-2,200 rpm band where the Borla resonates. Fitment is direct-fit (MagnaFlow 3D-scanned the chassis) and the rear fascia tips are reused like the Borla.
What We Like
- + Larger 2.5" mandrel-bent piping flows better than the 2.25" Borla — the right choice if you already have, or plan to add, downpipes.
- + Six straight-through tuned-chamber mufflers reduce cruise drone noticeably compared to the Borla — the more daily-friendly choice.
- + MagnaFlow Limited Lifetime warranty plus CNC-precision robotic manufacturing for consistent fitment.
Things to Consider
- – No version integrates with the 2022-2023 active-valve hardware — Borla 140936 is the only valve-compatible system in our catalog.
- – Tone is deeper but slightly less “musical” than Borla’s polyphonic character — some Stinger owners prefer the Borla note for that reason.
MagnaFlow’s straight-through tuned-chamber mufflers prioritize lower drone at cruise.
Finishing the Look: Borla Carbon Fiber Tip Kit
Neither Borla S-Type nor the MagnaFlow includes new exhaust tips — both reuse the factory valance tips. That is fine for stealth builds, but for owners who want the finished look that completes a Borla cat-back, the Borla 20165 quad 4" rolled carbon fiber tip kit was engineered as the visual companion. It uses a hybrid construction (rolled carbon fiber outer shell over an aircraft-grade T-304 stainless inner sleeve), so heat tolerance is genuine — these will not blue or peel like dress-up tips. Fitment is paired with the Borla cat-back, not the OEM exhaust.
Hybrid construction: rolled carbon fiber over T-304 stainless — heat-tolerant, not dress-up.
Borla S-Type vs MagnaFlow Performance: Quick Comparison
Both systems are premium 100% stainless cat-backs from blue-chip US brands, both come with lifetime warranties, and both bolt on without a tune. The differences are about pipe diameter, drone behavior, and whether you need active-valve compatibility. Here is how they line up at a glance for the 2018-2021 cars where buyers can choose either:
| Feature | Borla S-Type (140736) | MagnaFlow Performance (19406) |
|---|---|---|
| Pipe Diameter | 2.25" True Dual | 2.5" Mandrel-Bent |
| Material | T-304 Stainless | 100% Stainless |
| Muffler Design | Polyphonic Harmonizer | Straight-Through Tuned Chamber |
| Sound Character | Deep, layered, harmonized | Deeper, more open |
| Cruise Drone | Mild, 1,500-2,200 rpm | Lower than Borla |
| Active Valve (22-23) | No (use 140936 for 22-23) | No |
| Warranty | Million-Mile | Limited Lifetime |
| Price | $1,699.99 | $2,064.00 |
What to Expect: Sound, Power, and Install Reality
Sound on the 3.3 Twin-Turbo
Both systems unmask the V6 dramatically compared to stock, which most owners describe as a 1-2 out of 10. On a 1-10 scale where straight-pipes are a 10, the Borla S-Type lands around a 6-7 and the MagnaFlow about a 6, depending on whether you have the carbon tip kit installed. Idle is mild on both. Under boost the Borla has more harmonic layering — that signature polyphonic character — while the MagnaFlow is a deeper, more open growl. Twin-turbo flow softens the high-frequency rasp you sometimes hear from a Mustang or Camaro cat-back, so neither sounds drone-ey on cold starts.
Realistic Power Gains
Vendor marketing for Stinger cat-backs sometimes quotes 30+ horsepower — that is optimistic. Independent dyno data on comparable twin-turbo V6 cat-backs (and Stinger Forum dyno threads on the 3.3) suggest 5 to 15 wheel horsepower is the honest range, with similar torque gains in the midrange. Where the cat-back actually shines on a twin-turbo engine is reduced back-pressure spike during shifts and freer-revving feel above 4,500 rpm. No tune is needed because the system is downstream of the cats and O2 sensors. If you want big power gains, downpipes plus a Stage 1 tune is the next step.
Install Time and Difficulty
All three systems are bolt-on. With a lift, our Tampa techs typically finish a Borla install in about two hours. DIY on jack stands in your driveway runs two to four hours, depending on how stuck the factory clamps are. Soak the OEM hardware in penetrating oil the night before — it saves real time. Hangers and clamps are reused, no welding is required, and the rear fascia tips slot back in (or get swapped for the carbon fiber kit). Tools needed: jack stands or lift, 15 mm and 17 mm sockets, a pry bar, and the usual hangers/penetrant. Borla and MagnaFlow both ship clamps and gaskets in the kit.
Frequently Asked Questions
Does a cat-back exhaust add horsepower to the Kia Stinger 3.3 Twin-Turbo?
Yes, but modestly. Realistic gains fall in the 5-15 wheel horsepower range with no tune. The Stinger is unusual because the factory mufflers use 1-7/8" tubing crushed to clear the rear axles, which genuinely restricts flow — so cat-back gains are real here even though they are often overstated on naturally-aspirated cars. Vendor marketing claiming 30+ hp from a cat-back alone is optimistic. Expect a freer-revving feel, modest top-end gain, and noticeably more sound character.
Does a cat-back exhaust void the Kia powertrain warranty?
No, not blanket. Under the Magnuson-Moss Warranty Act, a dealer cannot void your factory warranty just because an aftermarket part is installed. They must prove the cat-back directly caused a specific failure. Since a cat-back operates entirely downstream of the cats, O2 sensors, and turbos, tying it to a powertrain claim is nearly impossible. Emissions components are not touched. Practical risk is very low for a bolt-on cat-back swap.
How loud is the Borla S-Type on a Kia Stinger?
Borla does not publish a Stinger-specific decibel number. Across other applications tested to SAE J1492, S-Type systems measure roughly 92-101 dB at wide-open throttle. On the Stinger, owners rate the Borla S-Type about a 6-7 out of 10 compared with stock at 1-2 and straight pipes at 10. Idle is mild. The aggressive character shows up under load and falls back to civil at light cruise.
Does the Borla S-Type drone on the Stinger?
Mildly, between roughly 1,500 and 2,200 rpm under light load. Borla markets the S-Type as drone-free, but real-world owner reports describe noticeable cabin resonance in that band — manageable, not loud enough to interrupt conversation. The MagnaFlow Competition Series drones less at cruise thanks to its straight-through tuned-chamber mufflers, so if a quiet highway is your priority, the MagnaFlow 19406 is the safer pick.
What is the difference between the 2018-2021 and 2022-2023 Borla systems?
The 2022 model-year refresh added a factory active-valve exhaust that opens in Sport mode. The Borla 140936 part for 2022-2023 cars includes integrated valve hardware that ties into that OEM actuator so dual-personality functionality is preserved. The 140736 part for 2018-2021 cars has no valve. Both systems use the same 2.25" T-304 piping, Merge X-Pipe, and Polyphonic Harmonizer mufflers. The valve hardware is the reason the 22-23 part costs roughly $500 more.
Do I need a tune after installing a cat-back exhaust?
No. A cat-back sits downstream of the catalytic converters and O2 sensors, so the ECU sees no change and no fuel trim adjustment is required. Tuning becomes a consideration only if you swap primary or secondary downpipes, add a high-flow intake plus charge pipes, or upgrade the turbos. For a standalone Borla or MagnaFlow cat-back, you can install and drive without touching the ECU.
Can I keep the factory exhaust tips with a Borla cat-back?
Yes — both Borla cat-back systems (140736 and 140936) are designed to reuse the factory rear-valance tips. No tips are included in the kit. If you want to upgrade the look, the Borla 20165 quad 4" rolled carbon fiber tip kit slots into the factory valance cutouts and is engineered to mate directly with the Borla cat-back. Note the carbon fiber tip kit will not fit the OEM exhaust and has year and trim restrictions for the 2021 model year.
How long does it take to install a Borla cat-back on a Kia Stinger?
A skilled installer with a lift typically finishes in about two hours. DIY on jack stands generally runs two to four hours, longer if the factory hardware is corroded. Soak the OEM clamps with penetrating oil the night before — it saves significant time. The system is fully bolt-on, reuses factory hangers, requires no welding, and uses common hand tools. Borla includes all required clamps, gaskets, and hardware in the kit.
Ready to Wake Up Your Kia Stinger GT?
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