Could anyone list the cars that have aero and appearance upgrades that aren’t just the Forza upgrades? I’d be very grateful for the person who has the time to list them and I’m sure the community would too. Thank you.
Try manteomax.com - it is setup by one of the mods here and he usually has a listing for each car including aero.
You may also try Milouse’s site, Kudos Prime.
There may also be a list here in either the Tuner’s lounge or the General Discussion you could search for.
Hi lancer 
I havent seen a list of that anywhere but it tends to be the Classics (Remove Chrome) Muscle cars (Add blowers), SUV/Offroad cars (Bodykits, lights etc.) and tuners/rally cars (Bodykits) and a few cars with spoilers which you can remove (Jag XFR-S, BMW M235i for example)