VRSF 3″ Race Downpipes for the S58 G80/G82/G83 M3, M4. These 3″ downpipes are the best bang for the buck mod available for your S58, with gains from 27hp & 33tq when tuned. By eliminating the restrictive catalytic converters in the factory downpipes, back pressure is reduced significantly which results in faster spool, an increase in power & a more aggressive exhaust note