A quote from an Oz RS3 owner this morning about his replacement
"Ok folks I've picked mine up. I can confirm the part is indeed called "silencer", with the part number as listed by Stephen. The tinny rattle is essentially completely gone and as a result there is a noticeable improvement in the overall sound, particularly when the valves are closed. The timbre of the sound is thankfully unchanged and volume wise I'm pretty sure it's actually even slightly louder although I could be wrong. There is a very slight squeaking sound from the back of the exhaust although I suspect it's simply due to being brand new (I've only driven it the few kilometers home from the dealership and that's it)."
And he quotes a part number
"Hey guys. I believe I just had this fix done today. The part was a weird special order and they told me the same thing...it was about the length of the car. I have the euro (but oem) bypass pipes and at first they noted they were non-stock but my SA found the Audi part #s. Anyhow, this is the part number of what they replaced...and the retail price was almost $1800:
8V5-253-181CP "Silencer" -- I think this is the entire mid-rear section of the exhaust including the valves. I noticed that Cars245.com doesn't even have the "CP" revision in their system yet, only the CF version of this part number."
Although the part number he quotes isn't that new........but he says it sorted his issues.