I have a Team Orion wasp .12 with a dynomite pipe in mine & it rips. I also have a HPI ball dif, The stock dif is kind of weak but the ball dif might be hard to find. I also just put a F4i Modelsport Racing titanium chassis on it & it can use the steering bell cranks from a associated rc10 st. I don't have them yet but I am getting them this weekend. For a servo go with something with at least 80oz in torque & metal gears. Here are a few pics of mine.
[link=http://www.teamorion.com]team orion[/link]
[link=http://www.f4iracing.com]f4iracing[/link]