According to a comment from the game's developer over on the Steam forums, the game's progress is stored in a file called "progress.dat"
So if anyone gets all the cars / tracks unlocked and wants to post that file, he said that anyone else could download it and use that file as "a quick and dirty cheat."
Hint, hint, for anyone who feels like helping out.
Here's the link to the developer's comment:Link
...sounds to me like he doesn't mind us putting that file up for others to download.