What do you guys think about Arch's physics mods? They definitely feel different than the original Kunos cars, but is their handling actually so much more realistic than the original models??
If we ignore things like opinions from people who haven't driven said cars in question, or who don't know anything empirical about said cars in question, in my own opinion as the author, who has been there for the entire development cycle and has discussed with the test drivers whenever there was one available (Not so many people have driven a '74 RSR 911 but quite a few have driven an A80 Supra), I can say this:
I use KS load curves, so the mods will never be "100% accurate", as with any other car in AC. I don't use extended physics suspensions, so in some case, the cars will be somewhat noticeably inaccurate as well. Aero and tire data is either nonexistent or extremely limited for these cars, so they won't be as accurate as some better made racecars in that regard. Not all of them have laserscanned suspension geometries either, and AC doesn't have bushing flex, so there will be an inaccuracy there as well. The things pile on and if you look at it empirically, you could be mistaken to say they're bad.
However they still line up to drivers' expectations almost completely (For the Supra and GT86 I got just minor critique from track drivers and owners which was fixed via more accurate ARBs, for example), they line up to video footage almost completely, they line up to any tested metrics almost completely and they line up to any known mechanical values almost completely.
Considering this it's extremely foolish to claim that they're "not that good" compared to their original counterpart.
To boil it down simply, KS roadcars (And I am told racecars as well by people who know) are simply hacked together in an afternoon and tweaked via tires, ARBs and so on to produce handling which is somewhat correct and might feel right.
I do it the hard but more proper way. The result is a car that's more accurate empirically and generally especially when the JDM pack is concerned, will be much easier to drive; because the real car is better. I've gotten some criticism for that, claiming I "only make cars easier to drive", which I consider a compliment, because sim cars are generally too hard to drive.
However you're free to believe whatever you want. The question to "Are they so much more realistic than KS cars?" is still a definitive "Yes" by anyone who knows anything about these cars. You would come to that conclusion too if you studied it, so I suggest you only listen to people who are informed enough to give an intellectual opinion.
As an example, I'm sure someone out there likes the KS Supra or the KS Yellowbird or the KS R34 better than mine and thinks mine are junk, but it's quite foolish to claim that if you've actually opened those cars and know what the parameters should be.