Very thoughtful information. The two questions I have is what is the difference between the 350 and 450 chassis. Is it just suspension, or is transmission, rear end, and frame upgraded also. I have a slide now in my class A, it has never given me any problem. When I worked in aerospace when ever large cut outs in the airframe were required for say a sliding door the surrounding structure was always beefed up to support the large cut out. I would assume that the eng's that design the house structure did the same. The down side was always weight. Do you guys know of side walls failing because of slides?