One very minor flaw in the game is that only about 200 of these cars have the full treatment in terms of the raw beauty of their renders, while the rest look like more typical playstation cars.
There is a mind boggling number of cars and karts available for upgrading, and there are several layers of upgrades each car can have. You could spend the rest of your life in the garage, tinkering with different cars, and never run out of things to do. The game takes this a step farther by shaking the screen to simulate the same rough ride you might get from testing out these cars, and if you’re playing during a rain storm you can almost feel the rain as it sprays across your wind shield. This means if you add speed to a car that wasn’t designed for it, you’re going to get a car that is as wild and hard to control as if you’d done it to the real thing.