The problem with the revo-style slippers with something as powerfull as brushless is that they need to be tightened down pretty hard, and then the part that the pads are on flexes so just the inside edge portion of the pads are contacting the disk making it slip even more.
Never had a problem with my "RevoSpec" slipper in my 3905 Maxx... It weighs ~13lbs on 6s with a 1520. So...
Even still you can get the Hot Racing Double slipper with 6 Traxxas Al pads and have a GREAT Slipper system. I know that would hold up to whatever you throw at it...
Maxx - FLM, MMM, CD Med.36x706s
Raja - FLM Ext. MM, 1512, 4s
SC8ight - MMM, 1520, 6s
D8T - MMM 1717 6s