PETG would be suitable.
Plenty of people online. I also do commission work.
Is it as easy as saying PETG is good for all RC car parts? I would imagine the material and printing technology is dependant on the part and the properties required by it - a double AA kids toy is likely to need different parts to a li-ion brushless beast.
If its a plastic clip, battery holder etc then sure, a FDM part would be fine. But, if it's part of a wishbone then you probably want a printing technology with a more uniform strength like SLS (depending on the car's weight, speed, forces, etc). Or, even further if it's a turbo-nutter nitro or brushless car and the original parts are metal (I would imagine something like the drivetrain gears), then you probably need to look at direct metal laser sintering...
For some reason I have it in the back of my head that PETG is hygroscopic, so will that be dimensionally (or structurally) consistent if the RC car is used outside and gets wet regularly? (just thinking out aloud)
Then you need to think about bearing faces and critical moving parts - 3d printed parts (especially FDM) aren't renowned for their dimensional longevity as location features when also used as a bearing surface (holes soon become oval). In the past I've had to use POM (or even Oilite) sleeves/bushings in 3d printed parts, to keep holes true when supporting quickly rotating shafts.
It's basically a "how long is a piece of string" question without explicitly stating the part and its requirements (and the material of the original part, if there is one). (which I why i originally walked away from answering
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