Download the templates and use them to cut the plywood body. Use a laser cutter, or cut with hand or power tools. Sand edges.
Run each bolt through a wheel, a spacer, the car body, another spacer, another wheel, and a locknut to cap it off. (Remove the wheel's internal spacer if necessary.)
The car is ready to roll! If you want, change a layer or two, or even redesign the whole thing.
Take the car body apart and apply wood glue between the layers. Reassemble, clamp, and let dry.
You now have a toy car that's ready for tons of abuse. It can go very, very fast. Little kids will have no problem moving it around, and bigger kids will enjoy whipping it off ramps to see how it performs.
There's lots of room for customization. Make the body profile realistic or more abstract. Give the car a front and back, or make it symmetrical. Play with the wheel size and the distance between the front and back wheels. Stain or paint can liven your car up, as well as extra details such as names or stickers. Make your car what you want it to be!