This game is a pile of questionable decisions by the developers, but somehow it all works very well.
Played it 10 years ago, stopped right before the final championship, I didn't had good memories from that time, mostly because of the T4 racing being very hard to control.
Last month I decided to revisit it because it has a split screen multiplayer and I had my bro visit me for few weeks. Even though he doesn't like racing we had an absolute blast racing against each other and against the bots. After he left I got him his own copy and we started playing multiplayer.
Racing in T1 and T2 cars as we did when playing splitscreen is super fun, the handling in this game is absolutely magnificent. Codemasters took a realistic sim handling model and tweaked a bunch of values to create this Initial D crazy handling. As a result, with about 80% of the massive car roster this game has you will be having a mad fun after just few minutes of practice.
Then there is the RPG progression mechanics - game has a system with buying cars, winning money for races, upgrading cars, but for whatever loony reason it is exclusive for the multiplayer mode and is locked behind the painfully slow levelling system. You also can't test the cars in Online mode, you can't open a game without a second player and weekly solo challenges are few, fixed and change every Friday.
But once you find your car, get it a good tune and find yourself some people to race with the game is an absolute blast. You can also move the cars to a higher class which cause them to get a new look.
Too bad you "can't buy" the game anymore. player base is very small, but if you know at which time to play you should have no problem finding a lobby.