the crower gear will cost you at cheapest $2000 for parts brand new.
when you get them instanled as said already get some work done to the head,
another good mod to do with the cams is the inlet manifold i ve heard a lot of great things on the skunk2 mani thats the one ill be purchasing.
but if you realy wanna know how much of a diffrerence the mods make as you do them, then take your car to the 400m track and have a few runs, then after your mod try again and see what improvement you made.