I believe they were about 2500 when new, so 800 sounds like a good deal to me for a carbon framed bike. Personally I would never buy a used carbon frame, not knowing if there are any underlying hair cracks to the carbon but thats just me. Make sure that the frame is the correct size for you. It looks really small to me, could be the picture though. How tall are you and what do you weigh, what size is the bike?