Well done on the research. Most miss these numbers. if you have the large pioneer rack the off-road ratings drops to 126lbs.
I see 200lb tents strapped to these backbone systems in videos all the time.
I made a couple of detailed videos showing the install process for the stealth platform and camp kitchen with icebox/dual drawer set up. I also had a top plate added with aluminum extrusions for extra storage capacity. I was tempted to install a shelf back there but takes it's place.
Stealth...
could be 100 different things. Need more info. Provide as many details as possible. What are you seeing? What are you hearing? Did you plug in a block heater?
I purchase and service mine at different dealers. I can't find one with everything. I have purchased in Arlington and Tyler. I service in Dallas proper.