Robin is it the Audi longitudinal 7 spd box youve driven or the transverse dry clutch 7 speed? They are very different units, the audi longitudinal still uses the wet clutch pack, but with significantly increased clutch plates for a smoother pickup, it also separates the gear and clutch reservoirs to decrease servicing and cross contamination and can deal with a hell of a lot more torque.
....S4 Avant longitudinal. Supercharged quattro with sports diff option 
Is the Mk6 GTI also 7-speed? I've forgotten. If driving in Manual mode I really don't see the need for a 7th gear but perhaps that's just my driving style. If using 'Auto' D-mode I suppose it improves fuel economy a fraction. The average car buyer is obsessed with fuel economy - I prefer fast performance and driving enjoyment, otherwise driving can easily become a dull chore A-B syndrome leading to boredom and less awareness and decreased road safety. I don't like comfortably numb (unless played by Pink Floyd).
Nice, bet that was good fun to drive!
No its the same 6 spd, the 7 spd dry clutch cant handle the torque level that the wet clutch can, so unless you go longitudinal you can only get the 6 spd with a bigger engine.
7 speed top gear ratio is 0.62 with a final drive of 4.09
6 speed top gear ratio is 0.71 with a final drive of 4.06 in the DSG GTI
So it would appear that the 7th spd is a massive overdrive gear for motorway cruising, hence you didnt find an advantage in performance terms.
