I wasn't asking for an opinion on what kind of car to buy, thanks. You gotta read peoples whole post before responding to save everyone time.
Yes, I read your entire post. After having 3 kids I can tell you a M3 will not be a good car to have with them. Maybe you'll only have one and you can do it, but also see about hauling their stuff around forever. Sorry to burst your bubble, but you are no longer free. And you say you are tall, I'm not and I find the M3 small but not tiny.
I had an Accord when we had our first in 1993 and it was OK, but 2&3 came together. We found out we were having twins on July 3rd and we bought our minivan on July 5th. One twin is on her 3rd car, the other still doesn't have a license. I waited 25 years to get something small again. We named our 2nd minivan Ozzie the Odyssey, but mostly we called it the effing minivan at the end.
And chill. We are only trying to help and make a little light of it. I get that the car is your first baby and you want it to work, but trust me it'll be tight. Seriously, consider upgrading to the MY if you can.