Yamaha Grizzly 660 differences

Hello All,

I own a 04' Grizzly and bought my wife a 05' Grizzly. I thought mine was impressive until I bought hers. The 05' has more power, torque, runs cooler, can plow through water without ever a sputter. According to Yamaha the only difference between a 04' and 05' is cosmetic - nothing mechanical changed. Mine is currently at a Yamaha dealer and they are going through the machine to try to see if a wrong CDI box (from a Rhino) got put in since the Rhino CDI box is tamed down or maybe try to determine anything different to explain the difference in machines.

Otherwise I'm going to buy an advanced CDI box and a silencer to gain power, but I still have a problem with it running hotter then hers. The 04' is the year Yahama added the venting under the gas tank so that is not the issue.

I'm leaning towards a Dynatek CDI box and a Big Gun exhaust - Any Suggestions?

Any input or suggestions would be helpful.