Sorry but, Please take this a constructive criticism, There is a lot of issues with your mod in general. 3D exterior wise it's fine. But as multiple people pointed out on Overtake (and from the reviews that are on the site) all cars re-use the same engine. Which we all know was not the case irl. Ontop of that it's an V8 twin turbo engine?
idk how much you know about 3D stuff (i don't know much) but T10 have an 1990's Indy car 3D model you can steal the engine from, Specifically the Lola T90 Chevy variant. At least that way you have an accurate engine to use, this also includes textures and wheels. (Edit: Just realized that the Lola T90 is only available on FM6 and not FM7. So the model has not been extracted and probably never will so forget this part)
The window is also not transparent? and a good chunk of the interior honestly look like they were made by melted cheese. The LCD display could use some fixing also, and those tire textures looks really bad, I'm pretty sure there are free 3D textures available on Overtake that you can use that fits these cars.
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The car audio could also either use an replacement, or find a better sample (i switched to VRC's)
In my honest opinion this mod needs work, and should have had some more time spent in the oven. I can assure you that asking around for texture work from people isn't bad. or asking for help in general. This is after all a mod that can be easily improved upon, and i most certainly hope that you are taking valid criticism serious and do end up updating this mod and not leave it as 1.0
Someone else on overtake also mentioned car performance all being the same but i'm going to tally that down to keeping it simple and making sure all cars are fairly balanced etc.