HKSTUDIE Exhaust System – BMW M3 G80 / G81 and M4 G82 Competition

OVERVIEW

HKSTUDIE is the BMW-only brand created by HKS and Studie AG, Japan's best-known BMW specialist. The HKSTUDIE exhaust for the G80/G81 M3 and G82 M4 Competition is a full stainless system built and welded in-house at HKS in Japan.

The factory G8X M exhaust already sounds like an M car, and HKSTUDIE found that swapping only the rear muffler barely changes it. So this system deletes the middle muffler and uses a straight, unrestricted pipe layout into a free-flowing main muffler. HKS measured up to 35 percent less exhaust resistance than stock, which brought quicker boost response low in the rev range and gains of up to 5 kW and 15 Nm on an otherwise stock car — more once the ECU is tuned to use the extra flow.

The muffler internals were developed through frequency analysis to keep the sub-100 Hz highway drone that cheaper exhausts suffer from at bay, while bringing out the 200 Hz-plus mid-range that sounds sporty at full throttle. The result is quiet at a cruise and loud when you want it. The quad tips are a nod to the BMW 3.0 CSL: thick-walled slash-cut tips with a blasted satin finish and sound-deadening inner slits. The system is certified to UN ECE R51.03 Phase 2.

SPECS

• Material: SUS304 stainless steel
• Layout: center muffler delete, straight pipe, unrestricted main muffler
• Main pipe diameter: 70 mm x2 stepping to 60.5 mm x2
• Tips: quad exit, 101.6 mm outer diameter, slash cut, blasted satin finish with inner slits
• Exhaust resistance: up to 35 percent lower than OEM (HKS flow bench)
• Gains on a stock car: up to +5 kW and +15 Nm
• Sound level (R51 test): 97 dB, idle 64 dB (OEM: 94 dB, idle 63 dB)
• Minimum ground clearance: 135 mm at the #2 mid pipe
• Includes exhaust valve flap
• Certification: UN ECE R51.03 Phase 2, JARI10240006P
• Shipping weight: 39 kg in two cartons
• Warranty: 2 years or 30,000 km
• Made in Japan

PARTS INCLUDED

• HKSTUDIE stainless cat-back exhaust system (mid pipes and main muffler with quad tips), supplied in two cartons
• Exhaust valve flap
• R51.03 certification plate
• Mounting hardware

TECH RESOURCES

• Required extras: none. This is a complete cat-back system that bolts to the factory catalyst section.
• Pairs with: the HKSTUDIE Coilover Suspension with Canceller. If the car is lowered, check clearance at the #2 mid pipe (135 mm minimum).
• Installation: professional installation recommended. The car is raised and supported, the factory system is unbolted behind the catalysts, and the HKSTUDIE system is hung on the OEM rubber mounts, aligned at the tips and torqued.
• Fitment: Competition models only (S58B30A, 375 kW / 510 PS), RWD and xDrive. HKSTUDIE does not list the M4 Convertible (G83), M3 CS or M4 CSL — confirm with us before ordering for those cars.
• Emissions and noise: no CARB EO is published for this exhaust — off-road / competition use only in California.
• Low-volume specialist part. Verify stock and lead time with us before ordering.
• Price is for the item only; labor is not included.

PART NUMBER

• HKSTUDIE-EX001 — HKSTUDIE Exhaust, BMW M3 G80 / G81 and M4 G82 Competition

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