Don't hurt your brain mate. The UFR is based off the UF1000, the XRR is based off the XRT, FZR based off the FZ50... seriously though, they are what they are. Made up cars, I don't pretend what they are or what wonder what they are based off of. There isn't much you can do with the knowledge of knowing what they are based off of unless you want to do a skin of a real car.