Hello It's not really theory, but I want to give you what I found in ProStreet (maybe you found it, but didn't published it; anyways, if it's published, then sry, I didn't found it ) If the pictures are too small, then sorry; I couldn't get best angle.
When racing on Autopolis and Autobahn Drift Course D, I found these cars:
1. Nissan 240SX Lowpoly, black model found on Autobahn course. It got some manufacturer emblems and tribal stripe.
2. Nissan 350Z Another decoration car found in Autobahn. It's stock and blue.
3. Porsche 911 GT2 And another car from Autobahn. It's red, and like Nissan 240SX lowpoly car, it's completely stock and it's got tribal vinyl through the car and some manufacturer emblems.
4. Porsche 911 GT3 Very similar to GT2 when being lowpoly model; it's also similarly painted, but unlike red GT2, GT3 is white with gray tribals. Also spoiler differs.
5. Lotus Elise Lowpoly car, which is blue and got f*cked up front shape (really ugly :/ ). Can be encountered in Autobahn, as far I randomly searched.
6. Mazdaspeed 3 Appears on both Autobahn and Autopolis. Like other cars, it got tribal stripe and manufacturer vinyls and it's stock. It's color is red.
7. Shelby GT500 Not tuned car (!) Only black and white vinyl stripe.
EDIT. I know also about Audi TT 3.2 quattro staying somewhere on Chicago Airfield, but I don't have any screenies for now.
nice one m8 i didnt even know Prostreet had low poly models since well... its prostreet. but i really dont find the point of having low poly cars since there are always crowds of ppl flooding the barriers and whats beyond them (the stances pretty much). also could you mark on the track map where you found these models? that would be nice if you could do that!