Physical copies of Rumble Racing for the PSP can sometimes be found at used game stores or through online marketplaces like eBay or Amazon.
Unlike standard racers, this game is about survival. You use power-ups like Tornadoes to clear the track in front of you, Oil Slicks to stall those behind, and Bombs to blast opponents off the road.
Note: Rumble Racing was never officially released as a UMD in all regions. The following applies to digital backups or homebrew-enabled PSPs.