Hi,
I'm sure you have them in the UK - you can find them all over the world. These are 1:10 scale, gas-(Nitro)-powered and radio controlled cars which are available at specialised toy and hobby shops - except the GT40 which is out of production....
Chassis are usually made from strong aluminium, combined with plastic and/or carbon parts. The bodys are made from clear lexan which you can paint the way you like - so you have the chance to produce a little replica of your replica!
Most bodys are interchangable with different kinds of chassis - it doesn't matter if you have a Tamiya, Kyosho, HPI or Carson chassis - only the body holes for fixing it may be different, and if the engine mount has another place you may need to add some holes for engine cooling - but that's no big deal.
Regards,
Volker