I've had a variety of tyres on my S8's over more than 10 years, all premium brands but 18's not 20's.
Of them I preferred the Dunlop and Continental slightly, though there was not a huge difference between any of them.
For "all year" use I slightly favoured Continental, though I've been using winter tyres for a while now.

+1 for p-zeros - love them.

Your post has reminded me to post a conclusion to this thread!

I ended up buying a pair of Super Sports at £230 each - the Vreds were £186 and I couldn't find anything else available

Early impressions they are quieter than the Pilot Sports that were on there and have coped fine in heavy rain so far

I'll be replacing the other 2 tyres after the winter so until then can't really comment on outright grip

Before the set I've got now I was running on Dunlops Sport and there were ok.

When it came to putting a new set a good specialist I know who does alloys, wheels and breaks all his live told me to try something different.

I wasn't that keen on it but when I looked at one of his car (couple of years old X5) with same tyres on I thought a tyre guy wouldn't put nankang style rubber on his wheels, would he?!?!?

So I went for it and I purchased a set of 4 Kumho Ecsta KU31 255/35/20 97Y

And I really really can't tell much bad about them, I really can't, and I do take grip level seriously and was ready to buy another set in case they were really ****, but to my surprise they are really good, dry and wet and wear is good as well.

I've read plenty of reviews about the same tyres but only the ones from owners of cars such as A8s, 7s, X5s, S class etc, heavy cars coz same tyre on a 1 ton car may perform differently on a 2 ton car.
And to my surprise everyone had positive experience with them.

And because over a year ago they were only £420 plus fitting you couldn't go wrong with that and selling them off after few miles wouldn't cost me much.

There is still plenty of meat on them but I do not drive a lot, but I'm agressive driver quiet often.
I'm due for a new set soon, but only because of the camber after lowering the suspension by 15mm front and 10mm rear.
Insides are pretty much gone where the 85-90% of tyre has even thread with fair amount of meat.

Same set will cost you £200 more today, 50% increase, is it because they are really good tyres or because inflation???
50% inflation is a bit to much in my opinion especially where most of the tyres stayed at almost same level or they went up only by 10-20%.

BUT, I am keen this time to try Dual Compound Toyo Proxes T1, not R with the Falken style thread.
I've been told that this is what Audi is recommending/putting on todays cars!?!?
The fact that they are dual compound (harder on the outside and softer on the inside) could benefit me more because of my camber, they wont go off that quickly on the inside.
Plus Toyo is not a **** brand in my opinion, but I'm not an super expert when comes to tyres.

I wont come back to Dunlops, but I' keen on trying Toyo's this time and I can't exclude Kumhos to be honest.
If non of them will end up on my wheels then Continentals would be my choice or possibly Yokohama's.

Michelin Pilot SuperSports (Found them a little scary in the wet with 535BHP/ 800+ NM in my old RS 6)
Michelin PS2's
Goodyear Eagle F1 Assy 2's

Budget that are still decent, Vredistein however you spell them Sesstnas...

I don't even consider anything else, the ContiSport contact 5's are supposed to be alright.