1. Different engine concepts: M3 V8 is a highreving sport-engine (up to 8400 rpm), 335i is a 6-cyl-twin turbo engine (max revs 7000) with a lot of torque.
2. M3's suspension is even sportier than 335i M's.
3. M3 has a M-differential if I'm right
4. M3 is an M3

335i just a BMW...
