Jack – Don’t buy a downpipe Except if the maker provides a HP boost estimate and a dyno chart. However, after the N54 warms up the downpipes are hardly recognizable. Idle Within the car will sound inventory. Average cruising and driving will bring about OE-like sounds as well. Dig to https://jaredpvae95284.fliplife-wiki.com/3407858/demystifying_downpipes_a_closer_look_at_catless_vs_catted_downpipes