I’ve looked all over the forums, but a buddy of mine bought a borla pro xs muffler for his m3 with the 2.5 inlet, however he is now getting a catback system and gave the muffler to me, I can’t figure out the diameter of my piping, and don’t want to just cut my muffler off and see since it is a daily driver and I don’t have access to a welder at the moment at the house. I’m guessing it’s probably a 2.25 but I could be wrong, thanks for the help!