GT-C's are f**kin expensive brand new. I know where you're coming from when you say you don't want to spend heaps of cash on wheels that don't fit.
With the disk type, you can look at the raysengineering site and they should have a list of different face designs. It ranges from I think it was H for high, M medium and L for low. The lower one would give you the most dish, but less brake clearance, higher face type, more for brake clearance. The list should also tell you if they'll clear the 4 pot brakes. From what I can remember, it was M for the front and L for the rears and they'll fit, BUT make sure for yourself or email them.
Good luck with it and post up some pics when they arrive.
Cheers