Ah, excellent time to ask.
I *believe* I finished the game. I got that flaky 'you've won enough kudos' screen that goes on to say continue racing and take the ultimate test in the global challenge, etc. etc. way back, but nothing since then.
(I think) I've unlocked all the secrets, and all the codes, and all the cars, and beat the aforementioned two tracks (I wasn't really paying attention to either of them... I was talking to a lab partner over the phone
). I then went into time attack and finished off any tracks that I hadn't already raced or hadn't earned a fastest time on.
So, I'm done, right? Is there anything else to be had?
In Chapter 14 or so, I had unlocked all the chapters (I used jokers on nearly everything, and I was averaging ~700K a race) and then started beating the unrestricted special races and then unlocked the car I used to finish the rest of the game, the Celica GT Four. It's my favorite car, even though it has a relatively low CPF compared to the Skyline, Lancer, etc.
I only truly used five cars in the game: MFG, Alfa Romeo Spyder, MR2, Audi TT Roadster (I *hate* the coupe), and the Celica. According to the game, the Celica has close to 1,000 miles on it (pretty freaking insane, eh?). Prior to chapter 14, most of the legwork was by the Audi TT.
Took me six months, but it's done! Whoo.