You're in the same spot I was when I started. The new z4 30i, and x3 30i has the same engine as the 328 but has a three stage intake manifold. So it CAN work but no one had tried it yet. Get in touch with active autowerk and they can give you more info.
'06 Arctic Metallic 325i | Sport Package | 6MT | Dinan Stage III suspension | Dinan exhaust | 330i manifold swap! Click here!
| Active Autowerke tune | 135i Brake Calipers | Deiselboost caliper brackets | E46 M3 front rotors