Out of curiosity I was over on partsland.com comparing the 97 XLT sp to the 97 XC 600. I knew the XC had the Xtra-10 and the XLT had the Xtra-12, other than that the only other difference I could find was the primary clutch spring. Gold in the XLT and dark blue/white in the XC. Interesting that the secondary on the XC didn't have a more aggressive set-up with a stiffer spring and steeper, progressive helix. Secondary set-ups and gearing were the same for both sleds. I have never ridden a 97 XC 600- were they much snappier than the XLT with just the stiffer primary?