Whats the difference in the 2.2 head and the 2.0 head?

The cam can be slightly advanced by installing the sprocket with the dowl on #3 I believe. Its not like its going to run like crap or anything with the cam slightly retarded, actually retarding the cam will help increase dynamic compression at higher rpms so it would do a little better on the interstate.

You can boost it atleast to 8 psi on stock compression if you intercool it. Doing it that way will also help make sure it isn't a slug before boost kicks in.

Most piston engines get a 2% increase max in power for every point of compression increased so if your truck was putting out 100 hp and you increased the compression from 8.6 to 9.6 the most you might gain is 2 hp. Realistically shaving the head is going to give you like .7 hp. Most of the time having machine work done to increase power output is only practical if you already have to have it done. Definatly smooth out the combustion chambers with some 600 grit sandpaper while you have it off though.