Well the 328 is 230hp stock. With an intake and PBX you get to about ~240HP
The 330 is 255HP stock with PBX and a good intake probably at about 260-265HP.
So the 3 stage 330 intake manifold and the software upgrade will probably put you into the 255-260HP zone. so about 25-30 HP gain for about $2000
or PBX + intake = ~10HP for about $600