Report:
Well, the SwivelsRus swivel has been installed by Hubby. The only obstacle was his figuring out how to remove the seat (8 bolts after removing a tough-to-take-off plastic moulding). Try as I might, I couldn't find more than general information on how to install the swivel in a Nissan NV 1500/2500/3500. The instructions (1 sheet) were useless. Another Nissan owner from the Nissan forum came to the rescue with the needed info.
Turning the seat around is somewhat of a hassle. Hubby had to remove the stock center console and put in a removable wood box. In order to turn the seat around, he has to remove the new box (easily) and open the passenger door a bit. Not difficult, but if he were trying to stealth camp, it is not a discreet process. But the comfort of the extra and comfortable cabin seat is well worth it.
As far as messing with the warranty, there is no drilling, no material modification to the vehicle. Though no DOT label, either.The wiring for the airbag and sensor were two plastic snap together (words escape me this morning) connectors. Unplug them from each other, put swivel in and then click them together. No idiot lights went on after he finished the install and turned on the engine.
One additional unforseen benefit came up-the seat has been elevated three inches. The NV hood is big and without my tush-cush pillow, I am a little old lady craning my neck trying to peer over the hood when pulling into a parking space. No more of that and now, sightseeing is greatly improved to boot. Good for me because he usually drives when we're in his van.
So yes, the concerns of sending SwivelsrUs the check for $544 in advance for the swivel were unfounded. No one will answer the phone, you can only deal with them via email and snail mail to send the check. The person with whom Hubby dealt with, Maria, only sells the swivels, her only help with installation questions is "follow the instruction sheet".
I just tried to upload a copy of the instruction sheet to no avail. I wasn't able to log on for hours earlier this morning, so I assume that the site is a bit squirrely since the update last night. I'll try again later.
Ted