Almost all the parts off the cougar 2 are easy to get.
Many parts from the XTR are interchangeble , wishbones , front+rear hubs , kickup plate .
All shocktowers are available at Fibrelyte.
Only parts hard to get are the diff pulleys.
When you got pro diffs in your cougar (ceramic balls)than brushless is no issue.
I run a LRP sphere with a novak 5.5t in my cougar , no problems at all.
A gearbox of a Club10 cougar is even better , gears still available , same as from a Rascal.
So when you want to run your cougar , run it.
http://www.oople.com/forums/showthread.php?t=25123
A cougar with club 10 gearbox and Orion 100a esc and LRP 3-star motor (6.5t)