I am still not sure if I want to get a 250F or a 450F. my last bike was a XR250 and I wound the thing out a lot just to get as much power out of it as possible. I've heard that 250Fs are not as reliable as the 450s because they are turned up so much to be competitive. I know I wouldn't wind out a 450 too much, so that would mean the piston would last longer. I ride mostly track and wide open fields, and very little trails. I am 5'8" and weigh 140 pounds. what i want to know is would a 450 be too much for me even if I took it real slow for the first few weeks?? also are the 450s reliable??? are they more reliable than the 250Fs??? I really think I could handle a 450 but I don't know if i should spend the extra money on one or not. 95% of my riding is jumping. are the 450s predictable jumpers????? what do you think would be best for me. keep in mind that all i want is a powerful reliable bike with good suspension for jumping.