Collection

B58

Performance downpipes and sport catalysts for the BMW B58 3.0L turbo I6. Direct bolt-on upgrades for the M340i, M440i, M240i, Z4 M40i and X3/X4 M40i — mandrel-bent T304 stainless, available catless or with a 200-cell high-flow catalyst, engineered and test-fitted in-house. Free tracked US shipping, made to order in 10–14 days, with fitment confirmed before you buy.

The B58 responds strongly to a freer-flowing exhaust: faster turbo spool, a deeper tone and the headroom your tune needs. Every OKTAN B58 part carries a lifetime warranty against manufacturing defects.