I don't think it is too much at all. My sons first car will be a beamer for sure.. Why do you ask? Safety. I know in my 530 you can govern the speed. Not to mention enough air bags to encase you in a pillow should shit hit the fan. Dynamic stability control is a + as well.
I don't know too many people who can say they have 5 people in a car and wreck at 75 mph only for all 5 to walk out unscathed...
2.5l is the smalest engine but the car will still move, so if you think your kid won't drive like an asshole then get it for him.
Will definatly help him out with pussy too =)
Edit to add: Parts and maitenace isn't cheap, but BMW is definatly one of the most reliable and best maintained vehicle on the road. Do your maintence when you are supposed to and you wont have any problems.
Last edit lol: Seriously make sure he doesn't drive like an asshole.

<---- A crappy pic but thats my baby.