Hmm, depending on the electronics your running, that's probably not heavy enough. A heavy mini helps prevent grip roll, as well as put the power down better. So try adding more weight. I'd suggest cramming a bunch in the bumper. Something else to remember, for my M05, with hobbywing 13T, I have to add about 20g extra to the bumper for close to 50/50 weight balance. I'm going to try to make a mould of the bumper and pour lead straight in there to remove some of the chassis weights from above the battery.

S-Grips on asphalt is an odd option? How are they lasting? S-Grips on carpet for me are lucky to make one meeting on the front. Have you tried Ride 3035 or M60 on the front with team powers 36 or shimzu 24sp on the rear?