I got a hold of a guy from Sound Marine Diesel LLC through the Pearson mailing list, who coached me through replacing mine via phone/email. It was pretty easy, I thought. I got a mixing elbow, an exhaust riser, and the coupler in the mail. Bought a bronze hose barb to fit in the mixing elbow down the street. Put them all together with a vice and a pipe wrench in my garage. Sound Marine guy also sent some exhaust-friendly thread locking agent with the parts for free in a ziplock bag. The hardest thing about my installation is that my muffler is right near my exhaust elbow, so there's not a lot of pipe running between them, and that exhaust pipe is a major PITA to bend. Also need to take great pains to avoid cracking your muffler. Hate that.
It probably would have been a lot easier if I hadn't been anchored off a rather small town in Costa Rica.
I sure wouldn't have wanted to have had one sent to me there. The other cruisers were saying that it took six weeks or more to get things sent from the states and it wasn't cheap.