I bought a used 2014 FWC Eagle shell. The previous owner had it bolted thru the floor onto his Ranger. I called the FWC factory, got their advice and thru bolted it to my 2009 Ford Ranger 4X4. Its been on the truck full time for 2 years. I've been off road on some pretty rough tracks and have not had any problems. I love the fact that I don't have to worry about turn buckles becoming loose.
My advice is to check with FWC they provide great customer support.
With regards to insurance, that's a involved topic. I have my FWC covered under a separate policy, so the truck has a policy, the FWC has a policy as well as our motorhome in which we live full-time. My insurance company required me to carry full-timers coverage on the FWC because we carry full-timers insurance on our motorhome. If you are not a full-time RVer, don't worry about the full-timer coverage. I tried a number of different insurance companies, but my choices are limited because there are not a lot of insurance companies that offer full-timers coverage. It all has to due with where your legal domicile is and your "garaging address". Mine happens to be Texas.
There is a thread about insurance on this forum somewhere.
2016 F150, FX4, XLT super cab
2019 FWC Hawk Shell
2009 Ford Ranger 4x4, XLT, Supercab total loss on 7/30/19
2014 FWC Shell total loss on 7/30/19
Towed behind our home which is a 2005 Kountry Star Diesel Pusher