You can also use a cooling system from a Firecat. It requires cutting the tunnel, but it works. I went with that route on my 06 SP, but I also have a 700 EFI in it, so I need a bit more cooling.
Otherwise, like mentioned, U-coolers are always an option. That would have been my next route...
2006 Arctic Cat SnoPro 440/700 EFI
1998 Arctic Cat ZR 600 EFI Custom
1996 Ski-Doo FormulaIII 600
A mountain lion roaming the prairie found a bull, killed it and ate the entire bull. With a heavy belly, unable to walk, the lion laid in the tall grass moaning and roaring. Soon a hunter, attracted by the roaring, shot and killed the lion.
Moral: When you're full of bull, keep your mouth shut!