Fitted the Acc yesterday and went out for about an hour - half of which was through traffic in Lincoln (+-5 Deg). I can report better town riding but still a little snatchy on roll on - roll off. On the road it seems to pull at low revs better but not sure if there is an improvement in power - still noted the 4000 rpm flat-spot. Also, I was looking for extra power so may have been more enthusiastic with the throttle which may have given the
perception of extra power, if you see what I mean......
I have the std OEM exhaust and can so the next step is catless headers.
All in all there is an improvement and for the bucks it is worth it.

Others with different exhaust set-up will obviously experience different.
Oh - re fuel consumption, the ave moved from 48.6 (500 miles plus with much motorway) to 48.7 so I will keep watching that.
OldCroc