Practicalities dictate that a lot of car kits and even more wheel kits are now sold.
The first kit for sale is a duplicate of a model I built, the Rosemeyer C Type Auto Union which won the 1937 Eifelrrnnen. The GTM kit is unstarted. This kit will require motor, gears, axles, bearings, guide and wiring + paint to complete.
Included is a kit to build 4 wheels with a scale diameter of 19". As per the real thing, each wheel has 42 inner spokes and 28 outer spokes.

The attached picture shows the car I built.