I agree with everything Surf. said. Great cars, probably more reliable than an AMG but also more expensive to fix. I've had mine for almost a year now and absolutely no problems. As for the transition from a Beemer, I sold my '01 M3 for the Maser. and absolutely love it. It is a lot more quirky and the controls (esp. the Nav.) are poorly thought out but a lot more fun than my M3. If you plan to track the car, you'll find that it drives comperable to your 645 around corners but definitely faster.
A lightly used '04 or '05 is the way to go.
A lightly used '04 or '05 is the way to go.