I just replaced the switch in my son's Megatech truck (same as yours). The wiring going to the switch either melted or was poorly soldering. It was tiny gauge wire anyway. These little trucks have great initial acceleration and immediate torque, but they don't do 25mph stock with a nimh pack anyway.
I also had to buy shocks, so I bought their aluminum ones. The front ones are really short, even with moving the mounts, it lost some "clearance". The ends like to come off the shock shaft even on the new ones. I guess you get what you pay for, maybe I'll try some MIni T shocks.