Crewe to Inverness (around 400miles) easy did it on one tank (showing 80miles left when I arrived). Bog standard GTI sat at 70mph on the motorways and 50-60 on the single carriageways, Driver & 1 passenger running on 95RON Unleaded. display was showing around 42mpg.
Its not the car, its how you drive it
the whole point of VW putting the FSi technology in these engines is to SAVE fuel - so when your not WOT everywhere, they are actually quite good.