Hi there,
I picked my 59 plate GTD DSG about 3 months ago and before that I had a remaped Seat LCR. With the miles that you do, you must have fairly long journeys so I would say that you should be able to get 50-ish mpg, but it depends of course on how you drive. I had 18s on my LCR and now run the same Goodyear Eagle Assy 2's on the GTD and its so much more compliant over potholes and humps and in general. No more wincing when I see a bump coming!
I cant see the spec - its not loading up, but the cabin is a very nice place to be, and I find myself more chilled in my driving style as a result. I also got standard cruise control installed when I got it recently serviced and it makes driving even easier, especially coupled with DSG.
Yes it costs more, but its probably got a higher residual sale value, although that will drop as the MK7s get older I guess. When I was researching the car, I never really came across many major problems regarding the GTD, and even on this forum there isnt much to go by. Overall I'm really happy with the car, though coming from a mapped turbo, I'm enquiring about a remap to get a bit more oomph and also a touch more economy.
Wish I had found one with Xenons and rear LEDs though - really expensive to add afterwards!
Good luck with finding the one you want
Jonny