If I was 22 and in his shoes, I'm 31 btw; I'd want the M3 BAD. Looking back that would have been too much car for me at that age. Then again I wasn't making what this young man is making.
It's your call, obviously there are way better things you can do with your money and others have mentioned. But you know your life plan better than all of us. I'd def get an CPO'd one though, or look into a lease; that way you're not 30-50k in debt. If you do take the plunge enjoy it!
Oh yea, like I said I'm 31 and I passed on the M3 and went 335 M-sport Coupe. Did I save a lot of money with that decision? Yep. Do I still want an M3? Yep.