We had a tremendous advantage in the fact our chassis was already perfectly symmetrical from the wonderful CAD data we had. When you weld an original chassis together, it moves all over the place and it drives you crazy. So, the sub structure is no longer straight--even if you were careful and measured everything CORRECTLY. Welding warps things. Like I say, we were very lucky to have a symmetrical and orthogonal chassis to start with. It made mounting the body much, much easier.