6 Inch B58 Downpipe for Supra 3.0T & BMW M240i, M340i, 340i, 440i, M440i, 540i, 640i, 740i, 840i, X5, Z4 Select one:Catless to determine which JB4 harness

to determine which JB4 harness your vehicle requires

Compared to NGK plugs they offer longer life and do not require manual gapping during installation

the 1/8" gauge port on your fuel regulator

If you're running E85 or ethanol mixes in your VR30DDTT powered Infiniti

4L Hybrid Gas

6 Inch B58 Downpipe for Supra 3.0T & BMW M240i, M340i, 340i, 440i, M440i, 540i, 640i, 740i, 840i, X5, Z4 Select one:Catless to determine which JB4 harnessThe ARM 6" B58 Downpipe is one of the foundational upgrades for giving your B58 powered BMW more power, torque, and sound. The stock B58 downpipe comes from the factory with a catalyst that severely restricts exhaust flow, causing excessive backpressure with increased boost. Upgrading to the ARM 6" B58 Downpipe unlocks power, improves turbo spool, allows you to safely run stage 2+ tuning, all while improving the sound of your B58 powered BMW. The ARM