Just had the motor done last year, went .20 over,shaved the head, some porting, gave me a modest increase over base line on the dyno and a really broad torque curve. At 210 lbs with gear i find myself working the heck out of that bike with only a 12 paddle on, and the bike feels and handles heavy. After 5 years on this bike I definatly need a change. The ATK and Maico bikes seem very similar but i'm having a tough time finding feedback on those models along with the availability of parts an issue, the 570 Husaberg sounds promising as well if in fact its producing 65 hp, I might just make the jump to 4 stk even though my friends would never let me live it down.