Aiden – A downpipe generally is a good insert-on, and in terms of model I don’t have a powerful suggestion. I’d recommend emailing or calling EuroSportTuning.com. They are VAG industry experts. I’m obtaining the DP and phase II flash in the following pair weeks. Dyno charts and lots of youtube https://bmw10763.scrappingwiki.com/940843/5_simple_techniques_for_bmw_m3_g80_catted_downpipes