Let’s get real here. If you are buying an M3 you don’t care about money.
I have a 328 and have been in an M3 many times. Although I’ve thoroughly enjoyed the driving experience, I can honestly say if I had it to do over again, I would not buy this car.
• it’s too small (basically a two seater). As you know there is a backseat but it’s too small to carry anything more than a few groceries. When I bought this car I thought I led a two seater lifestyle. I don’t. I don’t have kids but I still need more room for my life (friends, equipment, surfboards, bicycles, stuff) than this car offers.
• the noise (wind, tire) is unacceptable. The noise is something you may not notice during test drives because your attention will be on other things (driving experience, handling, etc.), but it is bad. Better than my previous car but still quite bad.
The seals around the door are different in the sedan than in the coupe (so the sedan is quieter) but I don’t think the M3 comes in a sedan version and who would want an M3 in a sedan anyway? Even in the sedan the wheel noise is bad.
Have you considered the V8 version of the CLK?
If you are determined to get a BMW, you might want to look into a 330 with a Dinan upgrade. Not every BMW dealer is authorized to perform this upgrade but you can buy the car from one dealer and have the upgrade performed at a different dealership.
For the price of an M3 you can get a one year old (or in some cases a new) 5 series which provides a much richer (and quieter) driving experience. My ex had V8 5 series and that is the car to own if you can afford it. If you’re on a budget get a V6 5 series instead.
If this post is at all related to your other post about high end audio systems for your car don’t worry. Just get the premium audio option on your BMW and you’ll be quite happy. There’s no need to spring for anything beyond that.
Finally, remember that there are about 4-6 different factory seats you can have installed in your Bmer. Try to sample as many of them as you can and then make a choice rather than just taking the ones that come with your package (sport, winter, etc.)