Like I said earlier to go from 270 to 315+ is pretty impressive with just simple breathing mods and a tune.
For reference, the 4.6L 3-Valve V8s in the older Mustangs typically dynoed 315-330whp with intake, exhaust, and tune. Keep things in perspective and the 3.7 is fairly impressive.
Perspective is the operative word, of course. If you expect to to behave like an LSX when you cam it... you're in for nothing but disappointment!