RE: GST 7.7 Rock Crawlin'
I tried this with a MGT and it will work ok, but to be honest you would be better off buying a dedicated crawler..
But if you really want to use the GST the first thing you will need to do is LOCK all your diffs not just the center..
You will also want the clutch shoes to engage at lower rpms.. so use soft clutch springs and heavy clutch shoes... like these [link=http://www.novarcproducts.com/clutchshoes.html]CLICK ME[/link]
Run a nitro with the highest oil content you can find maybe hook up some sort of electric fan to blow over the engine to help with high temps.
Axial is coming out with a cheap rtr version of the ax10 which may be just what your looking for..