105,000 is a lot of miles. From what others have posted in other threads about the topic, Koni FSD shocks are likely a good choice. If it is feasible for you to get there, Henderson's Line-up Shop in Medford, Oregon, would give you unbeatable service - chassis ride and handling is their expertise, and they have state-of-the-art equipment to back them up. As a bonus reason to go there, Henderson's is a sponsor of the BAC, as well, and deserves our support. As Karl said, call Koni direct, or call Henderson's if you can get your coach to them. They will quote you the correct shock and price.
Link through the BAC site here,
http://www.beaveramb.org/, and click on the Henderson's logo on the right.
-Joel