Originally Posted by Flienlow
Not speaking of you personally, but the Royal "you".... How do you know the stuff that you decided to do will work, and wont be dangerous?
I will go out on a limb and say most RV builders build pretty close to the plans. Modifications tend to be mostly non-structural and/or cosmetic in nature, but where they are structural they tend to be parts/component upgrades, but not always. Some builders have done considerable mods. In some cases they are engineers (or know engineers) and crunched the numbers. Others have just winged it. Hopefully tech counselor inspections, or the DAR/FSDO/MIDO inspector catches anything not airworthy. As an aside, Van's plans are really assembly manuals and are not true plans as they don't contain dimensional data except for the few parts you are expected to fabricate out of raw stock.
IMO it is best to stick close to the plans -- it will be cheaper and faster in the long run. I personally think that most mods are in the nice to have vs. need to have category. But ask 3 different builders and you'll get 4 different opinions. However, in the end you need to build the plane you want, not the plane others want.
Truth in lending disclaimer: I do have a number of mods in my plane (overhead console with air, hard points for a belly pod, ground power point, etc).