I'm having an urge for an ipod portable racing game.

I'm looking for something along the lines of a Ridge Racer, or maybe Burnout if either of those are possible.

I don't mind getting better cars or better parts for my car as I go, but I'd rather not start out in a Ford Focus, and race through lots of laps to get a slightly faster, better tuned Ford Focus.

Also, I would like to stay away from both the more technical games like Gran Turismo, and the really game-y kart racing.

Suggestions, comments, questions?    

Im looking at two games.  Need for speed underground and Real Racing.  both have been reviewed well.  Anyone with hands on that can tell me what they liked about each?