A friend and I each just bought a Thunder Tiger Sparrowhawk VX. It was 149 US RTR with a AM radio. I pulled all the stock electronics off as soon as I opened the box. I put a Castle Creations Mamba Max Pro brushless system in it with a Spectrum DX3R radio.
The point is. I wanted to test this thing to its limits. I have not found that point yet. I put it on 4s lipo. It was a blast. High speed drifting on the asphalt felt like driving on ice. Then tried 6s. I couldnt tell much differance from 4s because the tires just spun so much.
In the end, this car is rock solid for a low price, and has many upgrades too.