The torque arms will help.
Go with some good vents on the side panels to get heat out.
What is your current clutch setup. (weights, spring, helix, secondary spring and gearing)
Also, MOST of the sleds that Ive looked at (900/700's) do not have the clutches shimmed correctly for the .020" side clearance, or the deflection set correctly.
The problem with the 900/700's is that you cannot align the clutches if they are off... there is no adjustment for this.
Good luck...
I'd go with the 3211115 belt if it were my sled.
The 2006 mounts were much improved over the 2005's... but can cause problems.
Also, the bolts that mount the front motor mount plate to the bulkhead are prone to breaking... replace those bolts with grade 8 or 9 bolts.... the same for the rear mounts.
The 2 bolts that hold the mounts to the engine are also prone to breakage... inspect them as well.