if i were you (and i wish i was cuz i'd be starting w/ PI heads) i'd go intercooled regardless of how much power you want to achieve. Yes it's more expensive, but you brought up engine safety - the biggest problem is usually PSI and the power adder, and not always the exact hp/tq number. Pushing a whole lot of hot air into the engine isn't exactly efficient or appreciated by the rotating assembly.
Look at hotmustang's TT engine, intercooled and relatively low boost for his numbers - having a turbo helps tho.
Roots or swin screw may be more strain than either centri or turbo.
So I'D save up lots of money and get the mongoose kit with one of tim's tunes and intercooler and then put some mild blower cams in. I'm sure you could make some VERY decent numbers with an overly safe set up there.