You won't be disappointed! One of the best sound systems I've heard and I've heard a lot of really high end systems including linn, bowers, harmon etc...
The only 2 systems I've found better in a car are the ones in the A8 and the £7000 meridian in the new range.
you clearly haven't heard any aftermarket systems then, manufacturer systems are way way overpriced. That £7K system would probably cost you not much over £1K in a decent car stereo store. ive always gone for decent sound systems spending £2-4K on aftermarket stuff
the b&o is a good quality option, but amazing? nope its acceptable and worth £750, ok top end, ok mid, not much punch/bass/low end. Having said that the B&o option was my 2nd option I selected after colour, as I couldn't live with the carpy standard sound, lol