The one that is puple is running a street bike engine from a gsxr 700 with nitrus. the yellow one is running a regular ds 650 engine that has been bored out to a 720cc and running a turbo on it. He said he was running between 20-25 pounds of boost from that turbo. I don't know any other mods he added to it, but it is fast. Really cool seeing it in person!!!