ZZNEWB, I'm really sorry to hear what happened to your leg. To make your ZipZap go faster, buy a whole bunch of Upgrades from Radioshack. Try the Layman's Dual/Tri Cell mod, and make sure you know how to charge it properly

This weighs as much as the stock battery, but with 3x the voltage, so you can try that for more power without the extra load. You could also take the gears from a KIT Racer and put them on a Zip axle to make a speedy gear ratio. Warning: The Kit gears are VERY fast in top end speed but not in acceleration. So you have to wait 10-15 seconds or so before your Zip burns some serious rubber.....The ZipZap shells are VERY stylish to me, but if this isn't satisfying enough, order some 1:64 scale slot car bodies and paint them from the INSIDE!!! Anyway, I hope this solves your problem!!!