Out of the 3 you mentioned, IER stands above the rest in terms of physics. IIRC URD has to build their physics based on limited resources and references available (in the case of GTE it should be very limited). I doubt Tommy's TCRs have manufacturer data though.
Overall it's difficult to access modern cars' data because of obvious reasons. If you are interested in a bit older stuff then you're in for a treat 'cause those from creators such as Stereo, aphidgod, Gary Paterson, Pessio, Patrik Marek (just to name a few) are incredible