Check out RCmart and ASIATEES they have alot stuff to these.
Atleast had, Very cheap. Tons of options when i did my Tamiya TT
i regret i did not buy a better competetion kit insteath.

That time Schumacher MI had same price like hop up TT.
and the Schumi was like 10x better car than this Tamiya.

Today these TT can be cool, like Vintage racing, stock almost.
And old style retro bodies. Like Mustang or old Camaro