S2000 Cat-Back Exhaust: HKS Hi-Power Review (00-09)

A Honda S2000 cat-back exhaust is the single mod that unlocks what the F20C and F22C were built to do: scream to a 9,000 rpm and 8,000 rpm redline with the muffling turned down. The factory system is quiet, heavy, and chokes the top end just as VTEC hands over. Swap it for a proper cat-back and the same roadster suddenly sounds like the track-bred four-cylinder it always was. In this review we put the HKS Hi-Power Exhaust front and center, then line it up against the HKS Hi-Power Racing Version and the value-leading Skunk2 MegaPower so 2000–2009 S2000 owners can pick the right pipe the first time.

Why the S2000 Exhaust Is the Mod That Matters

The exhaust is the highest-impact bolt-on for a naturally aspirated S2000 because the engine lives at the top of the tach. The AP1 (2000–2003 US) runs the 2.0L F20C rated near 240 hp at 8,300 rpm with a 9,000 rpm redline, while the AP2 (2004–2009) uses the 2.2L F22C1 at roughly 237 hp and 162 lb-ft with an 8,000 rpm redline. Both engines pull hardest above the VTEC crossover near 6,000 rpm – exactly where a restrictive factory muffler starts to cap airflow and swallow the sound. A free-flowing cat-back with mandrel-bent, larger-diameter piping lets the F-series breathe through that high-rpm zone and, just as importantly, lets you actually hear it.

Be realistic about numbers: on a stock, naturally aspirated S2000, a cat-back alone is a single-digit peak-horsepower gain in most cases. The real wins are a cleaner top-end pull, a livelier throttle response after VTEC engages, several pounds of weight removed from the tail of the car, and a soundtrack that transforms the driving experience. If you are chasing big power, the exhaust is step one in a header-and-tune package – but even on its own, it is the mod S2000 owners notice every single drive.

HKS Hi-Power Exhaust Review: Our Top Pick

The HKS Hi-Power is the exhaust that defined the S2000 sound for a generation. It is a full SUS304 stainless cat-back with roughly 60mm (about 2.36 in) mandrel-bent piping feeding the signature Hi-Power canister and a rolled 120mm-class tip. HKS tunes the Hi-Power line for a broad, muscular tone rather than an ear-splitting drone, which is why it remains the default choice for owners who drive their car on the street, on canyon roads, and to the occasional track day without wanting to remove it for the commute home. Part number 32003-AH007 is a direct bolt-on for 2002–2007 S2000 models.

How the HKS Hi-Power Compares to the Alternatives

All three of these systems are legitimate, well-built S2000 cat-backs – the right one depends on how loud you want to be and what you want to spend. The Hi-Power is the balanced daily-driver choice. The HKS Hi-Power Racing Version trades coating and some sound-deadening for a lighter, louder, more aggressive setup with a titanium tip. The Skunk2 MegaPower brings a dual-canister T-304 design and racing-derived engineering at the lowest price of the group.

HKS Hi-Power Racing Version: The Track-Day Pick

The Racing Version (part number 32701-BH001) is the louder, more focused sibling. It uses the same SUS304 stainless but ships with no coating and a titanium exhaust tip, shaving weight and turning up the volume for owners who want a race-car bark. It carries the widest fitment of the group, covering 2000–2009 S2000 models, so AP1 owners who miss out on the 02–07-specific Hi-Power can still get an HKS system. Expect noticeably more high-rpm intensity – and more drone at cruise – than the standard Hi-Power.

Skunk2 MegaPower 60mm: The Value Champion

Skunk2's MegaPower cat-back is the budget-friendly way into a real, dyno-developed S2000 exhaust. It is built from T-304 stainless, robotically TIG-welded, and uses CNC mandrel bends and 60mm (2.36 in) piping into a dual-canister setup that Skunk2 backs with more than 15 years of racing R&D. At around $822 it comes in hundreds of dollars under the HKS systems while still delivering a genuine top-end power bump and a deep, aggressive tone. For a first-time S2000 owner who wants to ditch the whisper-quiet factory can without spending flagship money, it is the smart buy.

Sound and Performance: What to Actually Expect

On a naturally aspirated S2000, all three cat-backs behave the same way on a dyno: expect a modest single-digit peak-horsepower gain, with the biggest improvement showing up as recovered airflow in the upper rev range above 6,000 rpm. That is where these engines make their power and where the factory muffler is most restrictive. Pair any of these systems with a header and a tune and the cat-back becomes the finishing piece that lets the whole package breathe.

The real reason owners buy an S2000 exhaust is the sound. The standard HKS Hi-Power gives you that unmistakable Honda VTEC wail with the volume kept sensible for daily use. The Racing Version is meaningfully louder with more drone at highway speed – ideal for a weekend or track car, a lot to live with on a long commute. The Skunk2 MegaPower splits the difference with a deep, purposeful note. If you spend a lot of time on the highway, the standard Hi-Power is the easiest to live with; if you want people three lanes over to hear VTEC engage, the Racing Version is your pipe.

Installation, Fitment and Hardware

All three systems are true bolt-on cat-backs that connect to the factory or an aftermarket header/test-pipe and require no cutting or welding. A DIY install in a home garage typically takes one to two hours with basic hand tools, a set of jack stands, and penetrating oil for the factory hardware – budget extra time if you are fighting 20-year-old rusted bolts. Double-check your model year against the fitment: the standard HKS Hi-Power is the 2002–2007 part, while the HKS Racing Version and Skunk2 MegaPower cover the full 2000–2009 run.

One piece of hardware worth adding to the cart: fresh exhaust mounts. The S2000's rubber hangers harden and crack with age, and a tired mount lets a new cat-back rattle against the chassis or drone more than it should. The Torque Solution Exhaust Mount Kit is a cheap insurance policy that keeps your new pipe hanging true and isolated.

At our Tampa, FL shop we always recommend replacing the exhaust gasket and, if they are seized, the factory nuts and studs during a cat-back swap so you get a leak-free seal on the first start-up. Browse the full range of S2000 exhaust hardware and systems in our exhaust collection.