Noone can answer your first question until you tell us what you plan to do with it. If you are going turbo/supercharger/nitrous or if your staying N/A.
List one of those and someone can give you a good estimate on power potential.
with a turbo and 16+psi you should break 500rwhp. i'm guessing you'll max out the heads around 550rwhp. but who knows? get the heads ported and some cams and the power will skyrocket.