The 03's are kind of fucked up when it comes to compression. If you have 110-120 psi or more then it's fine! The 03's came with a damn decompression hole that is in the cylinder. This makes it easier to pull over them monster twin's. The compression will be low untill the sled has started then the power valves block the hole to give the engine full compression. Kind of strange but that also explains why the 01 and 02's have 3-4 more Hp. You can send the jugs into SLP and they will plug the holes for about $30 per cylinder.
2003-05 Polaris models are equipped with a decompression hole. However, the exhaust valves do not completely seal the decompression hole as intended when in the open position. As a result, the motor bleeds off compression, reducing peak horsepower. At elevation, it can also allow the exhaust valves to close prematurely, resulting in loss of peak RPM and horsepower. Plugging the decompression holes eliminates compression bleed off problems and provides an additional 2 horsepower. Cylinders are needed for modification.