The dealer loaned us a new '07 XC90 which we drove
about 700 mi over the course of a week while our '05 XC90 V8 was in for some
work.

The loaner was the new 3.2 ltr 6-cylinder model, and it worked very
nicely --- and it got about 21MPG on hwy.  We do, however, prefer our V8
model which has more bells and whistles and delivers more power for better
gas mileage (close to 24MPG hwy -- this may have to do with the engine size
effort required move a vehicle this heavy).  The V8 loafs along at about
1700RPM when cruising in the 70MPH range.  The 6 cylinder worked a little
harder (about 2000RPM at the same speed).

The sticker on the '07 3.2 ltr loaner was right at 45K (it had some add-ons
but was not comparably equipped to our '05).  The sticker on our '05 V8 was
about 52K (with everything but the nav and video systems), and I think
that's up to about 54K in '07.