07 was the last year seadoos had bad exhaust valves in the supercharged models. If the part number of the valve had 72, it was bad, 75 was good. You can't know that until you pull the valve cover, which is more than a typical inspection entails. Also, the superchargers were originally built with ceramic clutch washers, which tended to crack and fall into the motor, damaging internal components and disabling the supercharger. These superchargers need to be rebuilt every 100hr, and if it's been rebuilt within the past 5 years or so, it has the updated, metal clutch washers. Non-supercharged skis still had bad valves, but the failure rate on them is extremely low. Those are good, reliable skis. It's not guaranteed that the valves will fail if it's supercharged, but it has happened to quite a number of people.