I have 2 TMaxx 2.5's - the only problem that I had was over heating. It would stall when it got to hot. I bought a temp gun and can adjust everything they way it needs, now no problems at all.
Well - I have 1 problem. My wife won't stop wrecking hers into things and breaking it.
But then again - if you are not breaking anything, then you are not driving right.