I think that I want to get a new sled because I have really outgrown my pro x 550. There is a polaris shift at my local dealer and he wats $6500 for it new plus alot taken of for my sled traded in. Does the shift have a lot more power then an 2004 xcsp 600 because i have ridden one and is the gas mileage better then an 2004 xcsp 600? Are the handle bar risers as tall as my pro x's handle bars?

The Shift is a great little sled for that price. It puts out a little more power then the XC 600 does, 120 vs 118. Feul milage will be about the same.
If you've got the stock riser on your Pro-X the bar height on the Shift will be fine for you. Personally, I'd be putting a 6 inch riser on it right off the bat. Add a set of bar hooks as well and you're good to go.