i've never been flipped off, but have noticed a general cold shoulder. There's no brotherhood with M car ownership in comparison to Evo or STi ownership.
Z4M guys don't wave at me, E46 guys think they're better than me, then when I'm washing my car on front of my house a Space Gray owner peel out on front of me showing off
okay, I'm just kidding about the last 2 parts (space gray peeling and E46), but seriously, no waves, no hellos. A few times I've gotten flashes or waves, but like 5 times in the last 2 years of ownership.