Boost for the sake of boost is bad. Lots of factors to deal with. There are Buick GN's that can run 10's all day long on 10-15 psi boost, while my car needs 25+ psi boost to run with them. If your engine can flow a lot of air than you'll see more hp as you increase boost. At 17 psi boost my car made 403 rwhp 545 rwtq and at 25-27 psi boost it made 593 rwhp 695 rwtq. For arguments sake, it was 10 psi increase. It bumped rwhp by 190. This yields 19 hp per psi boost on my pushrod 3.8L V6 engine...For smaller engines it should be less until you start hogging out the head(s) and going to more cam.

The LSx generation of V8 engines also flow very well and each psi boost increase yields significant amounts of hp.