The adsl2+ estimates are usually conservative. Road is normally more reliable than crow flies when it comes to distance.
With FTTC I doubt you'd get 78Mbps if the line length to cab is 1.1 km. You may get a higher speed for a short while if the cab is new, but crosstalk will soon eat at some of that as more users are added to the cab. All in all though your estimate looks fine and its not a loooooooong line.
Based on your requirements and what you need then out of the bunch of them and bearing in mind your budget, if it was me I'd be looking at the 8800AXL, VMG8324 or VMG8924. Another one to perhaps consider would be the
Netgear D6400They all contain the same chipset so performance wise much of a muchness. Each has their own glitches but as I mentioned earlier, we are a picky lot on here and most people may not have any issues. On the whole I can say I am very happy with my VMG8324 even though I do moan a wee bit about the firmware - its rock steady and the best performer for my line and the one I always go back to by choice. Seeee we are never 100% happy
There is another alternative just come on to the market with is the
TP-link Archer VR900 which also meets your requirements. There's a couple of us beta testing it atm and we cant say much yet until testing is complete. After which time I'll write a review, but Im not letting any cats out of the bag if I say the wifi is brilliant, but its very disappointing there's no proper stats.