im thinking of buying a 450f. i was wondering which year i should buy. im debating between the 05 and 06. i like the 05 for the 4 speed transmission but ive heard that the 06+ with the new style frames handle much better. what are some of your opinions?also what is the best exhaust for the 450. most of my riding is motocross and small off road tracks. i want loads of mid range power with good top but don't wanna loose any bottom. also what years did the auto decompression cams come in? i can't stand the decompression lever.