Active Autowerke Gen 2 Equal Length Mid Pipe - F8X M3 / M4For over 40 years, Active Autowerke has specialized in precision engineered BMW performance parts. The Gen 2 Equal Length Mid Pipe continues that tradition, developed to enhance both sound and performance for the F80 M3 and F82 F83 M4 equipped with the S55 engine. The S55s twin turbo design produces an uneven exhaust tone due to the unequal length of its front and rear downpipesresulting in an unbalanced, high pitched sound. Active Autowerkes equal