Talked to Sierra 2 days ago...
I talked to Sierra BMW 2 days ago about ordering the Akrapovic S-B3R1-RC/1 carbon fiber for my 310GS and they said they just shipped out the last 3 they had. They said it only takes about 3 days to get more in but I am not so sure about that as I have had a hard time finding one.
Motostorm.com looks like they have some (Italy) and
Biohazardcycles.com (USA) have 9 in warehouse (I ordered one)
Let me know if you are able to get one.