Best online racing game???

Ridge racer, carbo, f1, Motostorm and what is the best overall online game from all genres?

Motorstorm is pretty fun

is it possible to play need for speed underground 2 online on ps3???

I'd say it just depends on which style of racing you like best.

F1 - extremely realistic, requires solid racing lines even to compete
Motorstorm - off road rally goodness
Carbon - somewhat arcady street racing
RR7 - extremely arcady drift action