Keep in mind that most Firecat tunnel extensions will have a large cutout to fit the rear heat exchanger. The SnoPro model does not have this exchanger, so you would have a large hole there that would need filling in.
Also, if you are running the 02 style heat exchanger, you will need extended cooling rails to make the cooling system work.
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!