Best Porsche 718 Cayman GT4 Mods: 2020-2024 Exhaust & Tune

The Porsche 718 Cayman GT4 is a mid-engine, naturally aspirated sports car built from 2020 to 2024 on the 982 chassis, and the best 718 Cayman GT4 mods work with its 4.0L flat-six rather than against it. The GT4 makes 414 hp at 7,600 rpm and 309 lb-ft from 5,000–6,800 rpm from a naturally aspirated 3,995 cc engine that spins to an 8,000 rpm redline — so there is no boost to turn up, and the honest gains come from removing exhaust restriction, recalibrating the ECU, and fixing the chassis for track use. This guide rounds up the GT4 upgrades we actually stock and sell at NLP Performance in Tampa, FL, with the real manufacturer figures, the fitment traps, and the one thing almost every buyer's guide gets wrong about this car's exhaust.

What Makes the 718 Cayman GT4 (982) Different?

The 718 Cayman GT4 is a mid-engine, naturally aspirated sports car built by Porsche from 2020 to 2024 around a 4.0L flat-six derived from the 992-generation engine family. It is the last of a dying breed: no turbos, no hybrid assist, an 8,000 rpm redline, and a 6-speed manual as standard at launch. Porsche added the 7-speed PDK for the 2021 model year, which cut the 0–60 mph time from 4.2 seconds (manual) to 3.7 seconds (PDK). Top track speed is 188 mph and DIN curb weight is about 3,199 lb. It launched at $99,200 plus $1,250 destination.

Two facts drive every upgrade decision on this car. First, it is naturally aspirated — percentage gains from bolt-ons are small compared with a turbo platform, so chasing 100 hp with a muffler is fantasy. Second, and far more consequential: every 4.0L 718 — including US-market cars — leaves the factory with a gasoline particulate filter (GPF/OPF) in the exhaust path. Almost no store blog mentions it, and it is the single biggest reason owners are underwhelmed by a cat-back.

Why the GPF — Not the Muffler — Limits Your GT4 Exhaust

The GT4's exhaust path runs headers → catalytic converters → GPF-equipped over-axle link pipes → muffler, which means a slip-on or cat-back only replaces the last component in the chain. The particulate filter stays exactly where it is. That is why a $4,000–$9,000 exhaust on a stock GT4 buys you sound, weight loss, and single-digit-to-low-teens horsepower — not a transformation.

Akrapovic's published numbers make the hierarchy plain. The Slip-On Line alone is worth +4.8 kW (~6.4 hp) and +15.8 Nm (~11.7 lb-ft). Add Akrapovic's titanium link pipe set, which replaces the GPF-equipped over-axle pipes, and the same slip-on jumps to +11.6 kW (~15.6 hp) and +43.0 Nm (~31.7 lb-ft). Roughly two and a half times the gain — from deleting the restriction, not from a better muffler.

There is a catch, and it is a big one. Akrapovic states plainly that for OPF/GPF-equipped vehicles, remapping the ECU is mandatory when installing the link pipe set, and that its Race Line configuration is “intended for racing track use only” and “does not meet emission compliance requirements for street or highway use.” Removing emissions equipment from a street car is a Clean Air Act problem, not a gray area. Our position at NLP Performance: if the GT4 is road-registered, keep the GPF and buy the Slip-On Line. If it is a dedicated track car, the link pipes plus a proper tune are where the real gains are.

Best 718 Cayman GT4 Exhaust Upgrades

A quick note on how these are listed, because it confuses buyers constantly: all three Akrapovic options below are built on the same base part number, S-PO/TI/18/1. The only difference is which tail pipes come in the box. Akrapovic sells the Slip-On Line muffler unit without tips, and the titanium tail pipe sets (TP-T/S/27 natural, TP-T/S/28 black-coated) are separate parts. “Option 2” in the listing titles is retailer shorthand for the tip bundle, not an Akrapovic engineering designation.

1. Akrapovic Slip-On Line with Titanium Tail Pipes — Best Overall

This is the complete street answer: the titanium Slip-On Line muffler unit plus the natural sandblasted titanium tail pipe set (TP-T/S/27), in one part number. The mufflers are high-grade titanium with components cast in Akrapovic's in-house foundry, and the system saves 6.5 kg (14.3 lb) over the factory unit. Because it retains the GPF, no ECU remap is required and the car stays street-legal. Akrapovic describes the character as a rich, harmonic, high-frequency tone at high rpm over a deep bottom end, with no drone.

2. Akrapovic Slip-On Line with Black-Coated Titanium Tail Pipes

Mechanically identical to the option above — same muffler unit, same 6.5 kg saving, same figures — with the black-coated titanium tail pipe set (TP-T/S/28) instead of the natural finish. Priced the same at $9,159.22, so the decision is purely aesthetic. Black tips read better against Porsche's darker paint codes and the GT2 RS-style diffuser; natural titanium is the period-correct motorsport look.

3. Akrapovic Slip-On Line, Tail Pipes Not Included — If You Already Have Tips

The same S-PO/TI/18/1 muffler unit on its own, at $7,848.58. Buy this only if you are adding Akrapovic tail pipes separately or already own a set — the kit ships with the muffler unit, six nuts, and two rubber mounting pipes, and it will not bolt up as a finished exhaust without tips. Add the titanium tail pipe set at $1,310.64 and you land at exactly the same $9,159.22 as the bundled listing, so for most buyers the bundle is the simpler path.

4. aFe MACH Force-Xp 304SS Cat-Back — Best Value

At $4,158.00, the aFe MACH Force-Xp costs less than half the Akrapovic and still does the important things. It is 2-1/4 in to 2-1/2 in mandrel-bent, TIG-welded 304 stainless steel with a high-flow muffler and an integrated X-pipe that balances exhaust pulses and cuts cabin drone. Critically for a daily-driven GT4, it retains the factory exhaust valves, so the OEM sport-exhaust button still works. aFe's in-house dyno claims up to +11 hp and +29 lb-ft. It is a direct bolt-on to the factory flanges with no cutting. The trade-off versus Akrapovic is material: stainless is heavier than titanium, and aFe does not publish a system weight.

Akrapovic Slip-On Line: Pros and Cons

718 Cayman GT4 Upgrade Comparison

Every product below is confirmed to fit the 2020–2024 718 Cayman GT4 and is in stock at NLP Performance. Prices are current as of July 2026.

Does the 718 Cayman GT4 Need a Tune?

The GT4 does not require a tune after a slip-on or cat-back exhaust, but a COBB Accessport is the single best way to unlock what is left in the naturally aspirated 4.0L. Because there is no boost to raise, the Accessport works by optimizing ignition timing, cam phasing, and throttle mapping rather than forcing more air in. COBB's published Stage 1 figures for the GT4 and Spyder are +8.1% horsepower on 91 octane and +9.8% horsepower with +5.8% torque on 93 octane — honest numbers for an engine Porsche already calibrated close to its ceiling.

Worth knowing: COBB's own map notes show the 718 GTS 4.0 gains far more (up to +17.1% on 93 octane) because Porsche software-detunes it below the GT4. If you own the GT4, you are starting from the sharper calibration and should expect the smaller number. Both Accessport SKUs are 50-state legal, carrying CARB EO numbers including D-660-122 and D-660-150.

COBB Accessport V3 with PDK Flashing — For 2021+ PDK Cars

The version to buy if your GT4 has the 7-speed PDK that Porsche introduced for the 2021 model year. On top of ECU calibration it flashes the TCU, which is where PDK shift speed, clamping pressure, and shift logic live — the part that actually changes how a PDK GT4 feels. The handheld gives a 6-parameter gauge display, up to 10 hours of data logging, DTC read/clear, and built-in 0–60 and quarter-mile timing.

COBB Accessport V3 — ECU Flashing Only

The standard Accessport at $1,725.00, and the right choice for a 6-speed manual GT4 — there is no TCU to flash, so the PDK SKU buys you nothing. It ships preloaded with COBB's Stage 1 map, stores 50 to 100 calibrations, and reads and clears fault codes. Same 50-state CARB legality. For a manual GT4 owner, this plus a slip-on is the most cost-effective power-per-dollar combination in this guide.

Chassis and Alignment Upgrades for Track-Driven GT4s

A GT4 that sees track days runs out of chassis adjustment before it runs out of power. Porsche gives you a genuinely good platform — ball-jointed suspension, real camber adjustment, a 380 mm brake package — but the factory alignment range is tuned for road use. Three parts fix that, in ascending order of commitment.

KW Clubsport 3-Way coilovers ($11,894.00) are the top of the range: independently adjustable low-speed and high-speed compression plus rebound, with a TUV-approved adjustment range. We covered this kit in depth in our 718 Cayman GT4 KW Clubsport review — read that first if suspension is your next move. See the full KW Clubsport 3-Way kit for the 982 GT4, or browse our suspension collection.

At $408.47, adjustable trailing links are the cheapest meaningful alignment upgrade on a lowered GT4. Dropping ride height pulls the rear wheels out of their factory fore-aft position; adjustable trailing links let your alignment shop put the contact patch back where it belongs and equalize wheelbase side to side. Sold as a pair.

Finally, H&R Trak+ 5 mm DR wheel spacers ($89.96, down from $99.95) are the low-cost way to correct track width and clear aftermarket brake hardware. They are hubcentric to the GT4's 71.6 mm center bore with a 5x130 bolt pattern and 14x1.5 thread — use the correct extended bolts, and torque to spec.

Brake Pads for the GT4: Read Your Brake Package First

The right GT4 brake pad depends entirely on which rotors your car left the factory with, and getting this wrong is expensive. The standard GT4 runs 380 mm grey cast-iron rotors front and rear. The optional PCCB package runs 410 mm front and 390 mm rear carbon-ceramic rotors, roughly 50% lighter.

Here is the fact that almost no buyer's guide states: Hawk explicitly says its pads, including the DTC-70 race compound, are not compatible with carbon-ceramic rotors and are designed for iron/metal rotors only. If your GT4 has PCCB, DTC-70 pads are simply not an option, no matter what a fitment table tells you. That is why PCCB-to-iron conversions are common on track-driven GT4s — ceramics are expensive to consume and they narrow your pad choice to almost nothing.

If you do run iron rotors, match the compound to the use case honestly. Hawk's DTC-70 operates from 400°F to 1,600°F with an optimal window of 800°F to 1,200°F — it is a dedicated race compound with aggressive initial bite that will not behave well cold on a street drive. EBC Yellowstuff sits at the other end: EBC positions it as a fast-street and light-track pad (EBC states a stable friction coefficient of roughly 0.42 mu) and specifically recommends stepping up to Bluestuff or a race compound for dedicated track use. Most GT4 owners doing occasional HPDE days want something between the two — and they want it bedded in properly over the first 100 to 200 miles.