Its my understanding that the Gavin and SS have the exact same motor and rear end. The gavin has a larger relay (Couldn't a larger relay be put in a SS). The SS has an aluminum motor housing which I have heard helps with overheating. I am no electric engineer but wouldn't excessive motor heat lower burn time? The bulkheads in the SS and the entire battery carriage looks like its higher quality. Sucks that I would have to listen to all the stroke stuff if I go with a SS.