I had to laugh a bit to see that a full tires set for my (new to me) E30 cost as much as my front left tire for the M.
I had a 335, went on the AWD track and bought a Lexus to downsize. Loved Audi but after going on their forums to read up on Audi engines/issues/maintenance, I ran away. Bought the Lexus and enjoyed the brief moment of downsizing. The daily drive was miserable. 2 months later, couldn't really stand it, went car shopping again and bought the M3. The drive home from Atlanta to DC in the M3 brought happiness that downsizing could not. I rather keep the M3 and eat ramen then downsize again. My girlfriend loved the Lexus for the ride comfort, but realized I was not enjoying it, so she supported the M3 purchase knowing that it would make me happy.