I was out with my 154 3" 850 and my buddy had his 2011 M8 162 2.5". when the day was done I put in 16 litres and he had to add 20. all things were equal in what we were doing and where riding. I'm still in break in mode so I was quite surprised.
2 days on my sled so far at 50% breaking. Day 1 - fuel light came in at 50km, rode 68km, put in 30l. Day 2 - rode 76km, have yet to top it up, but didn't have a fuel light till 65km. This is pretty typical of what I saw with my T3 163