Active Autowerke Downpipes w/ GESI Cats — S55
Active Autowerke GESI-catted downpipes for the S55 — F80 M3, F82/F83 M4, F87 M2 Competition. Clears the factory restriction on both turbos while keeping high-flow cats in the pipes.
Construction
Hand-built 304 stainless, TIG-welded, with a casted upper V-band for precise fitment and a pair of 4" GESI G-Sport High Output (Gen 2) catalytic converters — rated for 500–850 hp, EPA-registered, 49-state / OBD2, no CEL. Not California-legal.
Where it fits in the build
Downpipe-side core of an S55 Stage 2 build; we tune around it. The Stage 2 Kit — S55 bundles parts + calibration for 8% under à la carte.
Fitment
BMW S55 — F80 M3, F82 M4, F83 M4 Convertible, F87 M2 Competition. Confirm your chassis in the selector.