After recieving a payrise at work and expecting a nice bundle of cash in the next couple of weeks, I'm looking to get rid of the family wagon and get something sportier.

4 Cars on the short lists atm:

E39 M5
E46 M3
996 911
RS4@2000/1

Am looking to spend@ £18K and it must be able to seat 2 nippers in the back.

Any views on the above cars?