I have a BSM with lots of carbon bits and the blacked out front end. Plus the MPE which I think attracts a lot of notice as it sounds amazing. Quite a few stares and thumbs up etc. was grabbing a burger for lunch with a friend earlier this week and a guy was getting into his GLE63 which is a beautiful SUV and he stopped and walked to the back end of my car to check. I'm assuming he was like 'what kind of fenders bulge like that??' as the m235 is very muted in styling. He probably didn't know about the M2. Now he does and it seemed like he approved.
other than that I wouldn't say it's an overly 'loud' car. Orange or austin metallic M4's or porsche's do a better job at head turning. Or crappy civics with fart cans etc.