My younger son and I raced R/C cars when he was about 10-14 years old. We raced 1/12th scale stock motor four cell pan cars and 1/10th scale four wheel drive Touring Car, also stock motor but with six cells, in the winter on an indoor carpet track. A local hobby shop then set up a smaller carpet track for the then new Mini Z's, so we raced that as well. We ran the F1 cars, mine being Montoya's Williams and his was Coultard's McLaren.
As Team Principle and our one and only sponsor, I really liked the Mini Z's. They were far more durable than the 1/12th and 1/10th cars, plus batteries were far cheaper. The biggest difference was tire cost - they just never wore on the Mini Z's. The 1/12th scale ran on foamies, so I had to have a tire lathe. The 1/10th touring ran on hand-out rubber, but we would each use up at least one set per evening of racing. At about $30 for a set of four, that got to be some rather expensive toy car racing.
Then we discovered outdoor gas 1/10th Touring Car. Same spec tires as the indoor electric, but running on asphalt with gas
really chewed them up. He ran the spec .12 ci three port motor, but I ran something really weird - an OS .26 ci four cycle that I bumped to a .30 with a new piston and sleeve.
We loved the outdoor gas, but boy did it get expensive. We finally decided to look into go-karts, because, believe it or not, the cost was not all that much more. And we could sit in them...
But then, alas, at the ripe old age of 14 he bought a '68 912 with a holed piston (for the princely sum of $2,000 - boy, those were the days...), and that was the end of our R/C car racing.
We wound up restoring it and converting to a 911 as his high school senior year project, but that's another story...