Someone posted that there were a couple of 2.0tdi s-lines on the audi website with some nice spec. at £19,999, personally £20k for an SE with no spec. wouldn't float my boat.
S-Line package is only £750 now, se is free and if you order before 31st dec you get loads of toys free too.
Friend just did a deal today, new 2.0T S-Line special edition with full leather, 18" alloys, full s-line spec., parking sensors, Nav+, centre armrest, dipping mirrors for £23,900.
That is the new 220bhp engine too.
Drive the deal are offering 12% on new A4's at the moment too, just got an emial today, remeber the A4 is in its run out year so Audi are now starting to throw loads of free spec at the cars to get them sold and keep the orders coming in, so buy wisely.
Also tdi audis sell really well used, you may be better to order a new one and sell yours privately.