[SLESTAK75]

I think the 250's generally "feel" about the same. Because of the greater torque and HP they are geared higher. So you can have higher top speed but acceleration and climbing power feel similar. If you were to gear a 250 the same as your 150 then you would really notice the difference in power. Just my take and 2 cents. I've heard some say that a big bored and stroked 150cc will beat a stock 250cc but as most know you lose some reliability. I feel that if you had the money to build a powerful 150 you could just as easily buy a new 250. For me , I don't have the means to fit an engine that needs different mounting setup. That is why I would stick with my 150 and mildly build it.