My advise: be suspicious!
There is one RNS-E auction on eBay active right now where everything which could be incorrect is incorrect. The seller advertises the unit as AUDI A6 RNS-E, 8E0 035 192 P and shows the picture you have posted as well as one from an A3.
Well, let’s start. The A3 picture is OK, there is a device which fits an A3. The other picture (the one you have posted too) is showing an A8/S8 D2. Doing some research you will see that this picture has actually been taken by Craigyb, a member here and on TyreSmoke.net, who installed an A6 unit in an A8. Something a beginner should not start with. There is no RNS-E for an A8 D2 and if you read his posts here and on TyreSmoke.net you will see that it was an interesting task where he described how he modified the faceplate to fit and how he installed the device. Doing some more research you will see that an A6 unit should have a part number starting with 4B0, that the 8E0 unit is for an A4 and that there is no "P" version of the A4 unit, at least not right now. The "INSTALATION TIPS" the seller refers to point right here to
www.navplus.us, so I suppose he doesn’t mind reading these comments. And it doesn't help that his feedback is private which doesn't let you see for what the seller sold in the past.
I'm not saying that this auction is a hoax. I'm just saying that based on the information the seller provides you have no idea what kind of device you are bidding on (what shape, whether it's working in your car or not and how it's actually looking). There are many auctions where at least the information provided sound right and which seem to show real pictures of the device you are bidding on.
That being said, the only A3 8P device known so far is the European unit 8P0 035 192 (no letter). There has to be a US unit but nobody has reported the part number yet (a guess would be 8P0 035 192B). And there are references to a HIGH LINE version of the European unit in MY 2006 cars but no part number has been reported for this either (could be 8P0 035 192C). If you are looking for an A3 8P unit, you definitely want one which starts with 8P0 and I would also request a picture of the top cover to see which part number is printed on the unit.
Good luck!