05/06 GT wheels on a fox?

Yes, but they may be sunken in slightly. If you have the SN95 track out back it may work nicely.

I know these wheels bolt onto SVO's with no problems.

The tires are taller, about 1", so you may get some rub in the wells if you are lowered
 
Yeah, the offset is way off for a Fox or even an SN-95. Seen lots of take off 05 wheels on SN-95s and they look like crap! They stick in 1-2 inches. Kills track width and looks. It would only be worse on a Fox because they have a shorter track.

Nick