Gregory is my little engineer, and on a recent trip to a lego shop, I brought back the lego power set, which is a battery-box+motor. It also comes with a direction-reversal switch, which has center-off or 3-position, so it's quite handy, here is what looks like a Deloran antenna from Back to the Future. The set has headlights, which you can tint.
I only built the body-work, all the decorating was done by Gregory.
Testing Thinking, Anyone?
18 minutes ago