I store stove pipe/spare tire/crane on the roof rack, and other items as needed. This still gives plenty of room to hang out at camp with a cold one. Love it.
A) My bus has very stiff springs and the extra weight of the rack actually made it a bit softer on the bumps, yet it is still stiff enough I don't really notice any extra sway on the turns. Worked great without having to haul 24 kids in the back to get the springs to flex.
B) Extra drag... on a barn door? going slooow?.. wasn't really a factor in my application. I have a top speed of 62mph and a very big flat windshield.
C) Mine is insured as a commercial vehicle for personal use like a work truck. So probably also not applicible to your situation. Didn't ask or tell anybody about the rack. (except everybody on here...
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