If you can't find any good ones then there are a number of urethane replacements on the market but, if you have the good fortune to have a decent set of treated SCX ones then they are definitely better. Tires are also a nightmare, a lot of SCX ones are rock hard and impervious to any treatment. There can be a 25% difference in maximum revs and they all let the smoke out eventually, whereas a Scalextric motor will last forever. As stated above you need an RX42B motor but these vary enormously and are notoriously unreliable. Not all SCX cars are equal though and you may have to buy several to get a good one. There have been at least four different Scalextric versions but only the final incarnation (COT sidewinder) is worth buying. Nobody uses the COT SCX versions because of the stub axles and low ground clearance of the splitter but the Scalextric COT versions are the only ones that are remotely competitive with the SCX cars. They corner on rails and gain huge amounts of time.
The SCX ones are far better in the handling department, if a little slower down the straights.
The track is wood/copper tape so plastic track and/or magnet racing may be different. We run box stock with no upgrades allowed. Our club's NASCAR championship has been won by an SCX car every year since 2012 despite some of our best racers' efforts with the Scalextric version.
