Yes you can race them. But then you can light fags with tenners as well. The Yokomo you have is probably worth a packet now and ZXR's in decent condition will fetch you a tidy 80-100 quid. Even the Traxxas might be woth something to someone.
Consider also that nowadays the motors are way more powerful than they ever were back then and the wear and tear on the old cars would be way too high it would really pay to get a new car which is built to handle the new stuff.
A secondhand B4 would be great to start out again and is what I got after a 10 year break
