I have a set of Trident carbon exhausts for a steamer. They have done about 15,000 miles in all weather. The carbon is in good nick, but the stainless steel really needs some TLC to make it all nice and shiny again :)
I paid £500 for them new, and have never really been that happy with them to be honest. They sound good and they look good, but I really think the fitting of the cans to the bike is bloody awful - as is the fitting of the carbon fibre cans to the pipes.
I will get some pictures up later!