For brute power, get the Thunder Tiger EK4. I have two of them. They accelerate as fast, or faster, than any truck out there, and that's stock out of the box. You don't need a bigger motor cause it's got the biggest already!

I have a MSJ 2-speed tranny in one of them and it is doing well over 50 mph. With a gear change, some guys are getting 60 mph on this setup.
If you give them too much throttle, they will wheelie all day long, hehe. Some folks say they wheelie too much, but I say that just means you gotta drive it. T-Maxx or Savage is easy, just stab the throttle to full and go. With the EK4, you gotta ease into it like a new girlfriend, if ya catch my drift
Seriously though, parts for EK4 are not stocked at many places. That's why I bash the living hell out of my T-Maxx or Savage, instead of the EK4. Much easier to find replacement parts for them.