I only just discovered this, and it's fantastic! Great job - love the callback to Test Drive, that took me completely by surprize and was awesome.
This has probably been suggested already, but if not, how about support for ultrawide monitors - or at least have an option to put black bars on the side so its presented at 16:9 for those that want that. For me, on a 21:9 monitor, you can see the graphics that are meant to be off screen and it's a bit distracting, although I also like that it can fill the full screen. So if it's not in the cards to have full ultrawide support, then just having that 'force 16:9' option would be great. No big deal for me, I just changed my resolution down.
Also the low-resolution mode is so good, and fits the style so well, may I suggest making that the default. Could just be me though.
Overall I really enjoyed it. Truly you did a fantastic job.
Now, how about a career mode with sponsors... just kidding, kinda.