Just checked out the AP website & looking at there dimensioning it looks as though the six pots will fit as they have a smaller offset & utilise a 28mm thick disc where as the 4 pots use the 32mm disc & have a larger offset.

Check out the two link & let me know what you think:-

http://www.apracing.com/car/caliper/data.asp

the 4 pot i am looking at is the CP5200 & the 6pot is the CP5570

Input much appreciated.
Regards
Andy