Ive heard that the VZ-B V Sped is hit or miss. Some people get a good life out of them and alot of others have problems after only 3 gallons, im gonna stay away from that engine. Also my old engine was a Novarossi N21B, and i wanna know how would a S5 compare to that, becuase im trying to save money here, but i want an engine faster then the N21B.