Basically we are sayng the same thing, I am just a little bit more negative than you since I think the tyre model alone doesn't grant rF2 existence... About Reiza and turbo I remember they worked on it (or reworked it) in order to suit their needs. When I said tyre model isn't perfect I was referring to lack of other physical effects (tyres and otherwise). You just worded it better than me lol but I learned Eng by myself so I need more text to be clear
We all like different things, and I am probably a minority, but I personally play rf2 not because of physics. Yes, physics are great, very detailed, especially in a motion system as one person mentioned already. However, I disagree that physics is all there is. rF2 has one of the richest penalty system, only (barely) surpassed by iRacing. Has safety car, yes, mostly broken, but it just needs a few fixes and someone on s397 who cares and has passion for that. It is rules and SC are what make me feel like in an autosport event, rather than free for all joyride. It has hands down best API data model, allowing for best CC integration of all games. Lastly, it is moddable. So at least to me it is not just tires/physics. And I think people who say "TM is overrated" mean that physics and is not all that makes a great game. My 2cts.
I know one of their content updates either introduced or reworked their turbo parameters (for their cars), but it didn't change what was in rF2 since 2013 or so. The rF2 turbo took too long to bring in (rF1 already had 'hacked' turbos available, rF2 took something like 18 months to get anything) but it was beautifully detailed and perfectly useable from day 1. Not easy to set up, though.