S58 engine RSS
BMW M3 & M4 G80 G82 Downpipe Guide — Catless vs 200-Cell, Power Gains, Sound & Fitment (2026)
The BMW S58 twin-turbo inline-six in the G80 M3 and G82 M4 is one of the most tunable engines BMW has ever built. Factory downpipes include restrictive catalytic converters that sit directly downstream of both turbochargers — creating significant backpressure right where exhaust gas velocity is highest. Replacing them with high-flow downpipes is the single most effective bolt-on modification for the S58 platform: reduced turbo lag, more peak power, lower exhaust gas temperatures, and a dramatically more aggressive exhaust note. This guide covers everything you need to know before buying downpipes for your G80 M3 or G82 M4: catless versus...