i think you need to do a lot more research then what you have. That set up at best is very incomplete, u will have to run engine mangament due to the higher compression pistions and cams, however u will not be albe to run an itr ecu becasue you will be using your gsr mainfold which is a two stage mainfold where the ITR is single Stage. There is much much more, but i would say RESEARCH if you have to ask if a GSR cam gear will work on an ITR camshaft you are far from ready to start building a motor.

best of luck!