I had 1500 miles on my 04 (MXZ) and the compression droped to 130 on the Mag and 150 on the PTO (1000'). I droped in a set of SPI's and now have 5000+ miles. Compression is still in the 148 PSI range. Kinda hard to see, but if you pull the "Y" pipe off and peek at the rings from the exhaust side you'll see some pitting in the center of the ring (when it happens). Doing the work is not a big deal, just takes time as the REV motor is fun to pull apart under the cross bars. It can be done, but I prefere to pull the motor and clean the bulkhead area.
