[snapdragon]

I replaced mine 5 years ago (also ASB). None were faulty, but I replaced them anyway as I enjoy tinkering. I used NGK Y-609AS but to be honest they were a tiny bit shorter at the tip (~3mm) but they do another one now that is not... Y-1002AS

I didn't have any problems removing them with a hot engine that had rested for about 20 minutes. I also soaked them in plus-gas spray a week before and again after stopping the engine before doing the job.

There was some aluminium from the head sort of smeared on the threads and they feel like they are gripping the aluminium too tight when unscrewing. You need 1/4" drive deep socket and wobble extension and a low-torque torque-wrench such as used on bicycles. It's really important to be square on to the plug when unscrewing to stop them snapping.

Some early A8's had ceramic plugs which are very fragile. Only in 2003-2004 IIRC. these had a different colour band on the collar (you will have to google it) and the ECU also gives them a different voltage so would need recoding if changing to metal plugs. Also double-check the part number corroborates on a webfew sites, as I found some trying to sell wrong ones.

Don't be too scared, but do stop if your gut instinct says so and leave a seized plug in.