me and my buddy made rc cars out of k'nex a long time ago. we used standard car electronics though, servo, 6 cell battery, esc ad the motor was smaller than 540. maybe 300ish. i usually did dual motors. had decent speed and did wheelies. made front shocks. they actually held up pretty good. once i put a nitro engine in one but didnt work out so well.... the car broke apart while trying to pull start the engine. good luck with your project. its fun and different. i was going to try legos once but its too small for the electronics i was using.