If you merely need a downpipe, hunt for one which comes along with a dyno chart demonstrating the expected performance improve. Normally, they increase ten-20hp by them selves. Im presently working a custom muffler but is there any additional good thing about a downpipe? and if mounted, must there be https://www.social-bookmarking.org/en/the-ultimate-guide-to-downpipes-for-bmw-m3-g80-maximize-performance