Well i'm not involved in a rc factory, but I do know a couple of things about the subject.
The ''RC Engineers'' do use a very simple tire model, at least the manufacturer I spoken to.
They don't use a program like ADAMS, because it is way too expensive for such a small company.
The thing they will do is some basic calculations with some math models, like rollcentre calculations, camber change, ackerman, caster change.
Currently i'm busy with designing a rc car while making use of the advanced simulation programs like ADAMS, Matlab/Simulink and some other motorsport specific programs.
I have the possibility to do this because the university I study at has all the various licenses for these programs.
I'm currently still testing with a stock Xray NT1 suspension to test the program because it is quite hard to accurately simulate an rc car.
I'm also planning to do some CFD work to test different rear wings and maybe do some underbody aero, trying to create some downforce.
The manufacturer was quite interested in what I am doing, so when I have some results he would like to see them.
It would be cool to have a full rig to test the cars, but for the rig to fully work you will probably need some track data/telemetry. Otherwise you can only do some basic shock testing.
If only AIM or any other would make a miniature data recording set, with shock potentiometers, load cells, ride height measurement.