Lee's original motor, a 1300 cc air cooled Yamaha was replaced with a Honda 1000 cc motor to keep it in F sports racing. For the most part the rules in sports racing are only governed by engine size and not much else. Lee was able to get class championships with using that car and his Stohr.Not true in the past - I believe we put it in one of the Sports Racer classes. I believe Lee Fjellanger ran his as an FSR if I am not mistaken?
I know there are two body styles for these cars or maybe interchangeable bodies - one has the wheels under bodywork and the other has open wheels but protected by bodywork front and back as well as rub rails preventing wheel overlap you would get in traditional open wheeled cars.
The current Stewards judgement always is the final say, but I never had any problem with them being in Sports Racer classification. They make their points on reliability and durability and will never be outright competitive on speed with true developed sports racers with similar displacements.