Here is another car that came RTR but I was not satisfied with the duration and top speed. Don't get me wrong, the original configuration with Reedy SC-800 and SL-550 motor worked great and was a lot of fun but I want it more torque to spin all 4 wheels on demand on asphalt effortlessly.
I started by upgrading to 11.1v Graphene Lipo with 65c discharge rate. Right away I started to notice the Reedy 550-SL was having a more difficult time with the extra weight. These Turnigy Graphene battery are heavy almost putting the truck to 1/8 scale weights. I tested different ESC with different motors and found the lower the KV, the more torque I get but I loose my top speed. So finally I settled on the 3600kv motor and matched it with a speed controller that can supply the current increase. Both motor and speed controller came from Thunder Tiger.
Here is a video the test runs.
https://youtu.be/p8SMhxpUzCU
Enjoy!