Excellent, it's great to know there are others with the same dilemma.
I have a demo ride set up (once it snows again on the concrete snow) on both the 09 M8 and M1000. I'll let you know my impressions.
After everything I read, the 153" M8's are showing the Xpee's their rear flap on the hills. The problem is no one seems to have seen how a 153" M8 and a 162" M8 compare on the hills.
I think that for a M1000 for me it's a done deal. If you go with the bigger sled, get the longer track.
I guess that's why the spring only LE models were offered with a 153" track on the M8 and 162" on the M1000.