sarks757, you can get the Sierra's at

http://sierragiant.com/index.htm

You will need to remove the sheeting from either side of the retract bay on the bottom. I then removed both ribs on the retract bay. I then made new ones out of 1/8" ply then used some good spruce for the gear rails measured how much room I needed and glued in the ribs. Next glued in the rails. You will need to beef up the wing spar no matter what because you have to cut some of it away. I cut two 1/4" ply doublers and epoxied them onto the spar one on each side of it. There are pics of the mods further back I would advise going back to at least about page 24 and reading to here. All is explained with some good pics. I can tell you that the Robarts will not hold up to the weight unless you grease every landing. They have some new ones coming but they are not here yet. I have the Sierra's and really like them.

Randy