I even put some coin in the arcade games for a while - I played the crap out of IDASv3 and IDAS5, which were the best of the series IMHO. The other games weren't so good.
The amazing thing about Initial D is, much of what they discuss in the racing is technically sound - and I realized this when I attended more and more events on the racetrack. The Toudou School guys are correct when they say that braking is the hardest thing to learn, and in extremis, you do turn using proper weight shifting instead of sawing at the wheel. Left-foot braking, a driving skill I never properly learned, does combat understeer in powerful FF cars (but only when done correctly). It was the show that encouraged me to learn throttle-blipping on downshifts, which eventually led to heel-and-toe - although it doesn't tell you that heel-and-toe is best done when under heavy braking, and that doing H&T in daily driving negates much of the smoothness it's supposed to preserve.
Of course some of the key points are exaggerated for the show, but almost all of them apply in real life. The closeness of the racing can be pretty ridiculous and dangerous in reality, though.
My main concern with Initial D is that its fans are beginning to forget the whole point of the anime - it's not the car, it's the driver.
Also, the whole undefeated streak thing is a little corny after so many episodes. If you've watched "Capeta," which is an anime on kart racing, it's just as satisfying without having to resort to cheesy plot devices as "undefeated streaks."