You are going to need the calipers, carriers, rotors, and pad for the fronts. You will need rear hubs from a 330 in addition to the calipers, carriers, rotors, and pads or else the parking brake won't work anymore. If you don't use or need the parking brake then you just need the same 330 components as the fronts.
330i and xi brakes are the same unlike the 325i and xi.
Oh and you will need 17in or larger wheels to accommodate the larger brakes if you don't already have them.