What makes the power difference then? I'd always thought the extra 20 bhp was down to the 110 having variable vanes, because the original sales brochure when I bought mine (2002) said variable geometry turbo for the 110, and didn't say that for the 90.

I was about to say "higher fuelling", but then it occurred to me that, if that was the case you could remap a 90 up to 140ish, the same as you can a 110, without needing any more changes than 110 injectors.

I managed to get just short of 70mpg(67-68 i think) according to the trip computer out of mine on the a run from Cheltenham to Truro and back at christmas, included a couple of days pootling the cornish lanes.