No way would I ever consider a DualLiner ... just as bad as the drop in ones from factory, too much water gets trapped in there and is doing nothing to protect against rust, in fact you are increasing the chances of rust because of all the trapped water down there ....
I just detailed a Ford Raptor with a DualLiner, 7 months old and it was already showing oxidation from the DualLiner it has, I showed the owner what it looked and he is going to get it sprayed ... I'm actually probably going to be doing it for him as soon as he puts together the money for it ....