you cant really go past stock RPM or boost levels with the S2 on the stock valve train.
if you want to run 30PSI you will need something like our 5040 spring kit.

 

Im gonna eun into this dilemma also..... I think Im gonna go S1 personally

 

Yeah there should be some etching engraved on the cams when you have the maker on the crankpully when its facing up when the valve cover is removed. You should see it on the left side pm me if you need to see pics to compare I myself have stage2"s from gsc.

 

i just got my s2's installed and upgraded with their springs and retainers.... do it n dont look back.