[Overdriven]

I have never liked only having rear brakes on an rc. And the thought of a 20+lb rc going 40+mph with only the rear brakes is a no no in my book. If you can afford it, get the front disc. Keeping the rear mechanical brakes may not be necessary, but it can't hurt. Its insurance and gives you a little more headroom with temps (esc + motor) on those hot days. Thats how I see it anyway.