If you drive a BMW, no one will ever give you a break in traffic. Everyone will just assume that you're a douche. But they're good enough to put up with the stigma.
In Europe, Audi is kind of taking over the douchebag stigma from BMW, but I don't think that widespread hatred of Audi drivers has taken hold in the US yet.
An M6 would be completely wasted unless you're an experienced performance driver. You'd be better off with a 650i or even a 540i.
Lexus is for people who don't care about cars.