Anyone considered changing the downpipe? On my M2 that provided a nice increase in volume and power, but kept it quite civil. Best of all there was no exhaust cutting.
I contacted CG precision regarding compatibility of their B58 catted downpipe with our 40i cars. They couldn't confirm it would fit as they haven't tried, but they were highly confident it would.
Given that, if someone is willing to try they will refund the item in case it does not fit.
If I had my car I'd try but my delivery is at least 3 months away!
Apparently this is the most popular B58 downpipe which does not throw a CEL.
https://www.cgprecision.com/#!/DS-1-...tegory=8896209