Warranty - which one?

[sloss]

My A8L 3.0 TDi is coming on 3 years old.

If I'm keeping it then I think I need a Warranty as it's had a few things go wrong and I shudder to think of a major gearbox problem or AC or the vast amount of lecky kit.

Audi struggled to fix the Air Bag Warnings - it was in and out like a rabbit down a burrow. If I was paying for that I'd not be happy.

Also the keyless button on the O/S/R door has failed again!

New brakes and discs fitted a week or so back and it's making 'graunching' noises so I'll note that at MoT time - booked for the 12th.

So, the question is, where is the best Warranty to be had?

Audi quote about £625, Warranty Direct and Warrantywise are both over £800.

What do I go for - a new Merc instead?