I wanted to answer the question if there is in fact a difference in power between a high-flow cat downpipe, and a catless downpipe. I am glad to report in the case of my BMW N55 there is no noticeable difference!

RVG High Flow Catted Downpipe
https://rvgperformance.com/product/hi...

Chapters
0:00 Intro
0:56 Stock DP Vs High-Flow Catted DP
2:46 Advantages of High-Flow Catted DP
4:08 Rules of the test
5:32 Results!
7:01 Ontro