OP says he wants something with 4 doors, sporty, decent gas mileage, and rare (335 common around him).
If he was talking M3 money... Why not 640 GC and on the cheaper end the 535i/ m sport? M3 sounds like everything he's not looking for. Only reason he's considering the M is because its a rareish bird.
There is the 335is ... But it still is just a fancy 335.