I finally found a good building game, sadly it lacked multiplayer.
The single player is fun, but short and the graphics are quite good compared to other PSP games. The customization is ok, but could need some more items and cheaper costume packs.
The most fun part about this game is making your own obstacle courses (For example, I made a mario level and a jungle obstacle course and I enjoy playing a mirrors edge obstacle course and trying to get best time in a online leaderboard) I also sometimes make racing tracks for fun, but there is only one car and I don't have the Turbo! add-on.
This game is not worth 30 $ or higher, but if you find it under that price and don't have anything else on your game shopping list, I reccomend getting it.