Thanks guys for the comments on mine,
As has been said they are a great strong engine and the MPG in my opinion is not to bad with my slightly heavy foot mine sat around 20.7 but since my remap 300 miles ago its been going up its currently sat at 21.9 and seems to still be rising, my experience of a 3.0 v6 remapped is like Paul said it really makes it come alive on the move such as on the motorway plant your foot and it pulls like a train,
Driven nicely I'm sure it would return 24-25mpg and all with the great sound of the V6,
Handling is great with the aid of the RS4 rear anti-roll bar and dropping which makes it a great joy to drive.
So to sum up the 3.0V6 IMO is a great engine to have in the Avant it's a joy to drive eats up motorways and still fun on the twisty stuff.