I had a new phone line and Infinity option 2 installed on Tuesday of last week (8th Feb). My IP Profile is 38717 kbps downstream and 10000 kbps upstream.
The checker on the Infinity website predicted that I was able to get an estimated connection of 28.7 Mbit downstream and 6.8 Mbit upstream.
Speedwise I tend to get a constant 37+ Mbit down and 8+ Mbit up regardless of the time of day.
My line is exactly 547m length from my home to the FTTC cab (BT engineer informed me of the line length when doing tests after installing the line and then Infinity).
You can't have Infinity without a BT line - end of story. Infinity is fibre to the cabinet which means your standard phone cable runs between your premises and the FTTC cab and the the new stuff from the FTTC cab to the exchange.
To get Infinity you also have to be able to get a min of 15 Mbit downstream. Lower than that and no Infinity (as my brother found out: he's estimated to be able to get 13.1 Mbit down and 5 Mbit up).
You can get details regarding Infinity from BTs Infinity website: link