Chances are you'll earn enough money to build up a steady collection of cars suitable for the different leagues. When you cycle through them at the dealership, you're told which ones are a good drift car, a supercar or a muscle car, and it's a good idea to own one of each - not least because certain challenges impose restrictions on the type of car allowed to enter.
Souping up the inner workings of your car seems pretty dull compared to completely changing how it looks on the outside. If you're really into shows such as the awesome Pimp My Ride, then the unbelievable amount of ways you can tinker with different types of paint, visual mods and decals will be your favourite game feature by far.
The Driver DNA feature also works really well, keeping track of your skills under the broad headings of drifting, circuit and gambling - and rating each of them as wild, sane or cool. Before every race you get to see each player's DNA, allowing you to make an informed choice as to whether to challenge them to a bet. Even if you aren't participating in a race you can still bet on the outcome.