Took the Kitty Wagon out for it's first run with a new configuration (new stuff: Turnigy 80A ESC, 3520 brushless motor, 2S Lipo, shiny electric mounting plates).
It's now bonkers quick, keeps lifting the front right wheel for some reason, and is basically uncontrollable at full throttle (spins out, flips over, or just sits there spinning the back wheels) - target achieved
Got ~40 minutes runtime, but couldn't really open it up due to a receiver issue (cut out at about a 10 meter range), which is probably for the best since the bearings are due for replacement! I think I need to invest in some decent radio gear