Intake is 2" already, so no need to go 3" on that end.
The exhaust is 3+", but there's no room between the end of the cvt cover and the bottom of the box frame.
Look for a thread called "Belt Housing Snorkel", its a pretty good design IMO. Only flaw I found was the water comes of the front tire and right into the intake, you'll need to shroud it some how. I used a "crazy carpet".
The thread is complete with a shopping list.
As for the impaired air movement and residual heat created by the 2" vs the 3" exhaust, you can lessen the affects.
One - move the intake from it's stock location, it sucks the hot air right over the engine exhaust into the cvt.
Two - The Dalton clutch cover has cooling fins built into it to aid in the cooling. You'll probably want that mod anyway.
Three - I've heard of a few people adding an axillary fan to force extra air through the system. I haven't tried this yet my self though.
All of these will help a bit.
I know any of the reliable contributers (like Todd) will say a snorkel is not worth the extra belt heat, but with our riding conditions in Manitoba the way they are, we simply don't have much choice.
The only complaint I have about the Teryx is that my belt is continually getting wet.
I have snorkeled my bike, and I have it at home in Winnipeg. If you'd like to come check it out, you are welcome. Drop me a PM and we can make a plan.
2010 Teryx LE,
Muzzy's Duel Exhaust
Dalton Clutch Kit
HW Overdrive Clutch Cover
K&N Modded Air Filter
HID Light bar
Odyssey PC925 Battery
Black Rhino gauge Pod (Tach, volt, W Temp)
Muzzy 840, Stage II cams, 38mm throttle bodies,
324 injectors, Water impeller,
new stock crank, rods and barring