I went for a ride around my buddies neighborhood on his studded up WR450 that he wants me to buy. There was about 4-6" of snow on packed snow roads. I got a lot of WTF looks while drifting around corners.
If I want a heavy bike I'll keep the XRR and buy another 2-smoke for the trails. Street legal is nice (XRR is "legal") but you give up so much with a 4-stroke here. My buddy doesn't like to hear that since he has a 530 Christini, Husaburg 570, and this WR450. I can't complain, he's letting me ride it this weekend.
If you like that stuff RideFreak, you should swing on buy our neck of the woods. I'll show you a few good trails. I enjoyed NM and the desert / rock riding. Way different then we have here!