I just replaced my stock 25"XTR's with 26" Maxxis Bighorn radials. Maxxis suggests 5lbs of air but I opted for 6 lbs in the front. My wife has GBC Dirt Tamers on her Kodiak and It requires very little steering effort so I had hopes that the Bighorns would help the AC and they did. It still isn't what you could call light but is much better.
Now for the XTR's. I had heard complaints about them breaking the seal between the bead and the rim. My tire dealer informed me that he had received several complaints from customers where the tire rolled off the rim. He told me he no longer carries XTR's in stock and will still sell them if someone wants to make a special order. After removing the XTR's I picked one up and the sidewall felt very soft and flexible. I notice AC has stopped using them on the new models and have gone with a Goodyear tire. If you have Carlisle XTR's you might up the air pressure to avoid these problems.