Rear brake disks and pads replacement
 

Looking at them I think they need replacing plus I got a vibration that started when I braked from 80-90 (sorry I meant 70), which has ome down now to around 30 so convinced ones warped (left rear)

Where do you get yours fom and which ones, in searching I'm finding 2 listed for a D3 4.2, the 280mm and 300mm.

Cheers

I got mine from eurocarparts.. They usually have the 3 letter build code in their description so you can pick the right size, then decide whether to buy from them or elsewhere.

I second http://www.eurocarparts.com/
The sale ends tonight I think. EDIT***Jan 1st midnight ****
Take a photo of the sticker in your wheel well for the codes.
These should match the codes on ECP website to make sure you get the right parts, e.g. 1LL, 1LJ, 1LM etc..

I would also then check ebay for price comparison.

you might want to check suspension components for worn bushes too

I agree with the above, had exactly the same problem with a company D3 A8 I told Audi I was 100% certain that the rear discs were warped, so they replaced them along with the pads. I had the car back less than half an hour, had to perform a bit of sharpish braking (idiot undertaking on the hard shoulder to 'dive' off the Mway) same problem all over again. I returned the car to Audi rather sheepishly;) they investigated and replaced a rear suspension arm or bush. Problem sorted. Hope this helps.

Paul