While the sound of the M3 V8 is nice, I'd much rather have a smaller, lighter car with a lightweight, powerful I4TT. I love my I6TT, but if a lighter engine (and car) can exceed the power/weight of my 135i, I'm in. In a few years the pendulum will swing even further to smaller and lighter. I hope M follows with simpler cars. Yes, I got my 135i fully loaded, but looking back, I'd go the simpler route.
BMW 135i Space Gray
/Glacier Aluminum MT
/M-Sport/ and ALMOST everything else