also, the RTR has a geared diff, the kit a ball diff.
The gear diff is great for low maintenance, but the ball diff has more adjustment.
I have the ball, but am going to fit the geared, as smoother. and i like low mainanence lol.
otherwise, not many big differences really.
just depends of you want to build it and add elecs or go the simple route.
I run mine in mid motor and 90% of others i know do as well, but as mentioned, if log grip etc, rear will be fine.