My original plan was to build my own and save some money, I paid more for these than I had thought would, but now seeing how much effort Roadtrek put into space management/use I can say I'm glad I didn't add this to my list of time sucker projects; getting both the static seat offset position and swivel offset measurements right would have taken me multiple attempts with a wood mock up. With the doors closed the door panel armrest just makes contact with, but isn't hard on the seat armrest, it takes a lot of measuring to make that happen..