would I have to change the valves also? and what kind of number do you think I would have with a nice tune with skunk2 cams, gears, valve springs, retainers, and valves?

 

valve stems are part of the valve. valve stem seals are the thing that is replaceable. they do not NEED to be replaced unless they are hard and old. but it is reccomended to do so.

with the pro 1s, on a stock itr, i dont know your exhaust system (header, cat included), but with a good set of bolt ons, you should be around 190whp.