CRG uses a 67mm PCD front hub. The rear hub is the standard 58mm. The KR is 69mm PCD front and rear. For more info on PCDs, check this info out.
As for AMV and CRG, we make a 67mm PCD front wheel for the 9F, 3F, and Tiger wheels. I believe 67mm PCD for Lynx is still under development.
Team Prodigy from Charlotte, North Carolina which campaigns Maranello karts is switching over all its 2 cycle karts (KA and X30) to AMV 9F wheels. They found the standard CRG made the kart too tight on hotter days and during longer runs. They are still testing the 9F on their four-cycle kart, but it appears they will switch those karts over to AMV wheels as well.
I am not certain if the CRG KT2 is different from the Maranello MK3, but I would assume they are pretty similar. I know the teams running the karts discuss and share setup information.
Please note that all the karts Prodigy has switched over, the karts changed the front axle to 58mm PCD hubs. 67mm PCD 9F front wheels will be arriving shortly – I hope.
If you would like more information on AMV wheels, you can find everything here.