ouch. Mustangs are fun... in a crude, single purpose way.
So the 330 comes with 225 crank HP stock and thats about all you'll get out of it. the ZHP performance package had hotter cams and some DME changes and makes 235 crank HP. I'm sure you can get a cold-air intake and remove some cats and get another 5 hp but then thats really it.
These cars are all-arounders. Good at everything but not great at 1 thing, until you start working in the suspension.
~ '02 330xi
~ '89 RX7 TII