My Flash has definately helped, adding about 10 miles to the typical range to warning light, so about 3mpg up, with a lot more grunt, very happy with that ::013::
Following the Mrs at a steady pace (but she still passes quite a few cars, and cruises about 70mph on straights) I can now easily see upper 50's (on our larger Gallons) and on a 35 mile trip on a windng country route managed a new best of an indicated 64.5mpg.
I now get upper 40's in mixed commuting / narrow back lane messing about, and it is harder to drop it into low 40's than it used to be, will know a whole lot more after my upcoming tour of 3000+ miles where I will measure MPG each day on a wide variety of roads.