Idea on rust protection

So I am not sure weather it makes sense or not but I am considering spending the money to have the entire underside of my rock warrior, cab and bed, sprayed with some thing like line-x or lizard skin bed liner material. Based on my mechanic and auto body tech schooling this will not only protect against rust but also give a sound deadening to the floor of the truck. Here in Illinois the salt on the roads in the winter can eat a truck up in just a few year, let alone the occasional gravel or dirt roads. Although the paint protection by the manufacturer has gotten better at doing its job I still feel there is room for improvement. I had the pleasure of working in a dealership once that would undercoat all new car when they got them in, most of the time using a soft rubbery coating that didn't need any real paint prep to make it stick. The idea was basically the same, coat and protect the cars as long as possible to retain the value, and keep customers happy and coming back. Of course this actually translates into more profit down the road for them, but lets not get into that. I have found a couple of places that will do what I want. Not only do I want the entire under side to the cab and bed coated but also to come up the sides and door jambs about 4 to six inch's, and possibly a little higher on the cab corners. Before anyone asks, yes it would follow all the way around the body and around the wheel wells. I do plan on putting fender flares on it at some point so no one would see the coating there anyway. I have seen entire vehicles coated in rhino liner at various car shows but I really don't like that look. I do believe line-x cas make a gloss finish and color match any base paint color. I am trying to keep in mind that this mod is going to cost me about $3000 and I have to come up with a feasible explanation to the wife to make it sound like it increases the value and longevity of the truck, any ideas on that point would be welcome. So if anyone has heard of this being done or have had it done themselves I would love some feed back. The more questions and responses the better of an "educated" decision I can make.

 

Have ya heard of fluid film? Some guys here like it....Check it out

 

Por15
works well for the areas you wouldn't want thick coating or if you would just like to use this as a base coat before doing line x etc. for added protection.
I used por15 on my full restore swap civic project(I know overkill for cali roads). It came out really nice aesthetically.
I did complete underbody, seam welds - engine bay, wheel wells, gas tank, and cabin. Painted over the por15 as well and base coat came out really good considering you can still see my brush streaks.