The Sepex motor upgrade to the Electric Motorsport GPR-S seems to function well, but acceleration is slower than the stock GPR-S PM motor version. The regeneration when braking feature works well and adds about 3% to the vehicle range under my riding conditions. It is activated when either brake lever is touched. My bike has a 72V system powered by 24 Hi Power (brand) LiFePo4 prismatic battery cells. The large 60 pound motor and heavier battery cells raise the vehicle's weight higher than advertised for the standard Etek-R powered version to around 330 pounds. The motorcycle chassis suspension is stiff due to the high carrying capacity of 560 pounds. The Tiger Boxer 250 chassis is made in Thailand and its design, assembly and component quality is comparable to similar vehicles from the early 1980's. The cost of this version of the GPR-S was $9,300.