3D Builder is great for loading up STL files quickly.
Your car has definitely lost that Audi LMP1 look.
I have uploaded my car, not sure how well it will do. Did a test with the version I posted a picture of in here and it had lost some rear downforce but it did have a COP that was slightly further forward that Matteos car originally had. Im not sure if the engine is getting enough air though. I have changed the rear wing and its supports from the version I posted and have also change the front wing plus removed the wing that was between the exhaust pipes.