Look dude if you want to fix it with Por15 then I say go for it. You've already got the best advice you're going to get. I've used Por15 before and it's fine for pinholes and cracks but it doesn't last forever and things like brake fluid will eat it up. Beside that there's no strength to it so something you're going to put pressure on like the floor is not going to work. Think of it like a thick paint. But you won't know till you spend a couple of hundred on supplies and are disappointed by the results. Or maybe you won't be. It's your car and you can do it several times if you want. Knock yourself out.