I think (joking aside) we'd all feel pretty bad if we unanimously told you to forget the warranty, and in a month the engine goes pop. However, I'd tend to say
if the Phaeton is the Omega-replacer that you hope it to be - then you shouldn't need a warranty (and there can't be many contenders, I've really thought the Phaeton, and maybe a big Volvo are the only cars left that are without a swanky-doo-dah bagde, but are still fine reliable cars in their own right. Perhaps a Skoda Superb if you wanted to go a car size down, but that's about it.)
I know that's perhaps a little trite of me to say 'you don't need a warranty' -
of course any new car/product should have one - but clearly this hasn't been a 'Friday Car' for you, and hasn't cost you a penny in unexpected costs, it's clearly a reliable, good motor, so there's nothing to suggest that with regular servicing, and all the maintenance that you should do, this car won't one day appear in your will

Also, I'd say that as these cars get older, Phaeton versions of OOF will appear and grow in strength and number, and all them little niggles which will invariably appear, can be sorted with clever hacks, and ingenious methods, as with the Omega. VAG is a brilliant company, and really makes sure their quality remains where it is. I could tell you a couple of stories of their fastidiousness (I know an ex-Head Designer) and if I weren't a Vauxhall man, I'd for sure be a VW nut
