The B58 and 4 cylinder F Chassis vehicles require a slight modification to the midpipe to get the proper fit with our F Chassis Valved System. The challenge comes in the difference between the midpipe angle. N55 equipped vehicles have a more staight midpipe exit than B58 and 4 cylinder cars. The way to solve this issue is to go to your local exhaust shop and have the mid pipe angle straightened in the last 10 inches of the mid pipe before bolting on the Valvetronic system. You can see in the picture below a F chassis system installed on a B58 340i. The only modification was to correct that angle in the midpipe allowing for an easy fit! This modification is super easy and is completely reversible. Although as it is possible to install your F chassis exhaust without this modification we do recommend it as it allows for better fitment of the exhaust system.
*ALSO APPLICABLE TO 4 CYL ENGINES*