Thanks Dave, thats encouraging to hear. Come to think of it you're right, I think I did notice my old S8 to be slightly faster when its nearly out of fuel.
I have been meaning to get a Performacebox for ages, its just the price that puts me off (close to £400). Nice that the new version links to the phone.
For now I will try the VCDS performance timer functin (alhough I read somewhere that its as much as 0.3s off) and I could try one of those free phone apps, although I have the very lowest model Winodows 8 phone, not sure if anyone has made a 0-60 app for those.
I cant wait to see the difference. Plus I need those leather seats, the alcantara is driving me nuts