I have a max 150psi tank, well that is what its rated for but i know they are underrated slightly. I don'think it's DOT because its not stamped that i can see. I wanna bump it up to 175 with a 140-175psi switch. My tank is not rusted inside and the welds look good. Is 175 excessive? I would like to go to 200 but that might be pushing it.