I'm not good with SCCA classes but I'm guessing that DSR is a D Sports Racer. Those cars are pretty sweet, light and fast with the bike motors in them. I drove a radical that had been fitted with a supercharged 1300cc bike motor at Roebling Road. They have a pretty insane amount of grip but you really have to be on your game to drive one at the limit when they let loose its not fun.