Hey, wanted to chime in.
1- The Line-x product is poly-urea and is applied hot using specialty equipment. It's very sturdy but isn't a DIY application. Because of all those things Line-x ain't cheap. End results vary based on the shop that's doing the install and the prep work. If the prep isn't correct, the material will separate or crack, trapping moisture below the coating and causing rust.
2- The stuff you see in home goods store is garbage. If you expect to beat the hell out of the paint and recoat, then you're good to go. If you're looking for longevity and UV protection against fading, don't settle.
3- There are 2 part epoxy style spray on or roll on materials that are readily available and DIY friendly. Both are tintable (you can choose color) and both carry guarantees against UV fading. Raptor liner and Monstaliner. I've used both and Raptor is slightly more DIY friendly because it almost never requires thinning and if you're going basic, is pretty much idiot proof. The final finish is up to you because it's regulated by application type and air supply pressure to the gun. The prep is simply but you've got to be diligent. You have to scuff up all panels to be painted and then clean them with water and a degreaser or manufacturer specified chemical.
Things to consider.
HVLP (air) painting and coating are hard to master to do well. If you linger too long the material buildup could run and streak or cause gumming and not provide an clean even finish. Have a plan with each pass. Where are you stopping, where are you starting. How do you plan to get back to that starting line to recoat after the first coat flashes.
If you're ever planning to sell the vehicle, don't spray the outside of it. Don't. I'd wager a large part of the market does not want it and questions as to what you're trying to hide. I've done a full body spray once and somewhat regret it. Really stoked I didn't do it on my pickup though so small victory there.
