I have not added shocks but here's a couple of links for your information.
http://www.shockwarehouse.com/cgi-bi..._retrokit.html
They have prices photo's and installation instructions in PDF documents. The table they provide is the one from MONROE.
http://www.monroeheavyduty.com/monro...e=retrofit_kit
In addition if you aren't a member of RV.NET there is a discussion there of people who upgraded their units with shocks.
http://www.rv.net/
I'm not sure if you can read the forum if you are not a member but give these links a try
http://www.rv.net/forum/index.cfm/fu...7.cfm#15340697
http://www.rv.net/forum/index.cfm/fu...6.cfm#15356286
http://www.rv.net/forum/index.cfm/fu...0.cfm#15077040
Best of luck in your travels.
Chris