While Zip Zaps are just cartoon versions of the Japanese "tuner" cars featured in the Fast and Furious movies, XMODS are designed to be meticulously accurate scale models of those tricked-out machines. That's why you don't see Ferraris and Lamborghinis. The first four are a 2003 Acura RSX, a 2001 Nissan Skyline (pictured), a 2000 Honda Civic, and, you betcha, a 1997 Toyota Supra.

The reason Radio Shack is going to make a lot of money on these little cars is that the $49.95 is just for the starter kit. The object is to fix up your car so it looks hot and runs hot, by buying all of the cool customization packages. And they really are cool: First, you deck the hull with authentically-reproduced body kits from Bomex or Versus. Then you pick up a set of engines to swap out for better torque and more RPMs, add head- and taillights, foam tires for better traction, suspension and steering upgrades and my favorite, an all-wheel-drive system to add front-end power to your car.

While an out-of-box "stock" racer may well take home the gran prix, some upgrades address inherent shortcomings in the product. Battery life ain't grand, so there's a set of rechargeable AAs. Moreover, the tools that come in the starter kit are almost unusable. After nearly spraining my hand, cracking my Supra's chassis and stripping a few screws in the process, I bought a nice fine-tipped Phillips head at the hardware store. Radio Shack is offering an XMODS Tool Kit as well.

The clever nickel-and-dime upgrade strategy isn't all that Radio Shack has in store for XMODS enthusiasts. Next April, they'll launch a 10 to 15 city racing tour. The races themselves will be held at malls and other establishments catering to "teens and young adults." Radio Shack will encourage racers to use only authentic upgrades, but adherence to the rules will be rewarded: the national champion might win a full-sized true-to-life version of one of the cars.