K60 - So far so good
The 150 section rears are available, I bought a set from these guys in the UK over e-bay, see the link they still have 4 in stock. I got them in 3 days in the UK so add a day or so to get them to you
Heidenau 150/70B-18 Enduro Tyre Tubeless K60 M+S (70T) on eBay (end time 13-Jun-10 14:19:24 BST)
I have run them for about 1000 miles of mixed road and trail riding and like them a lot. Need a bit more care on the road in the wet than the Scorps but nothing to worry about just work around, in the dry just pitch it in there round corners!
Off road a lot more grip, braking and steering on gravel, dry pack and rocks. Still not a full knobbly so not so good in deep mud or wet grass.
Slight knobbly noise/vibe when you are creeping along on tarmac at about 5MPH, otherwise as quiet as the Scorps.
They are reckoned to be about the longest lasting tyre for the ADV990, time will tell but I am optimistic looking at the relatively square profile as it sits on the rim and the tread pattern which plants plenty of rubber on the road when upright (which is where they all wear out first right?)
Overall - reccomended, moving to highly reccomended once they prove their durability.
Cheers - Martyn