Thanks 1badmofo! Its good to know that the suspension side of things will be grand!
Thinking about it more, Im sure I could just swap the 335i hubs and brakes onto the M3 subframe - since everyones already using all the rear M3 arms as upgrades, except the ones that hold the shocks as the 335i shocks are different (not joined the same at the base) compared to the M3 ones.
Mind you, I've be wrong before!!