I would not rush into ADSL Max. There have been significant teething problems since its introduction at the end of March. You will not see a vast difference unless you download large files regularly.
Also, I do not like BT's misleading ads which quote £14.99 but when you look further this price goes up after 3 months!
You can download a manual from click here=
And this link suggests it does support 8mps click here