RE: Cen GST 7.7 BRUSHLESS BUILD!
I would try the gst tranny first. I mean, three speeds with a brushless set up that thing would haul balls. If that don't work then definately go with a center diff. The good thing about the stockgst tranny is that it don't have the center lock in it yet so it won't wheelie as much as it would with the center lock in it. Even if you have to remove the gst tranny then atleast try to use the center diff from it that way it still wont just wheelie and you can actually punch it. All of the videos i see of the gst converted to brushless, it just wants to wheelie and never just take off. This would be my ideal brushless gst. I have the gst but i run an OS .30 in it and i'm a nitro junkie and just don't have room for electric in my life right now but when and if my motor goes i'll do a brushless conversion on it myself.
I have a video posted of a way to lock the external 2nd speed one way bearing and i recommend doing it because the brushless would tear up you one way bearing in a matter of a few runs. I'm pretty sure i posted it in these forums and if not then you can go on youtube and search gst one way bearing mod or something like that.
Anyways, good luck with the build and by the way i think that tecno mount would be perfect.