call Skunk 2 and ask if you could have the valve opening and closing degree specs for both.
In particular, you want to know the intake cam's closing point in degrees ABDC (After Bottom Dead Center).
Then ask Skunk2 what they would consider to be a good minimum dynamic compression ratio for these cams.
ITR pistons in a GSR will make 11.4:1 static CR using a 3 layer stock head gasket. If the stage 2 cams are like Jun spec 3's in terms of the intake valve ABDC closing point (in degrees ABDC), then 11.4 should be plenty for them. I don't know the stage 3 ABDC closing point, so I won't GUESS as to whether 11.4 is enough for them or not. As I said I have a link to a calculator to determine the dynamic CR once you enter the ABDC closing point spec here in one of the threads...just search under "dynamic compression".
Maybe SouLcHiLd1719 knows more about stage 3 cams than me to know whether 11.4 is enough but I can't guess and say definitely, yes that's good enough for the stage 3 cams.
it's a good chart graph to determain which is better for that set up.. but his is defferent. he would have less compresion..for the money skunk2's will work.
i my self have the skunk2 stage 3's.... but i also shift a 9 grand, 10 if i get a little crazy...with ITR pistions.
it's a graph in which the same engine package has only had the cams changed in it. Nothing else changed. If you know anything about scientific method, then, you will know this is the best way to tell if there is a difference attributable to that particular part. Clearly as we can see here, with adequate compression, there is ZERO difference between these cams. Why would you go to 10k when they don't make power past 9K?