I have pushed the S8 to 60mph on the speedo, but not for long. There is still a little bit of throttle left, but the motor gives me the impression of that's all it's got. Now granted, this is / was under 1k miles on the OD. Once i get past the 1500 mark, I may attempt to open it up a bit to see what the limit really is. Fortunately, the S8 150 offers just enough umph to get me through my daily commute; 45 - 60mph, avg commuting speed.