... well you might not be able to use the ION reg ... it might not fit your VA .... cuz of the weird threads that kingman have
Also if you wanta have an HPA tank you havta keep in mind .. that your gonna need a macroline hose kit for that reg of yours. You might needa replace your VA for the fittings too .. which means it would probably cost you about .. 25 bucks used which isn't really that bad
Also for better airflow so you can have more efficiency you can probably do some home mods .. as long as you have a drill, a lighter, and needle nose pliers ... but your also gonna need some sandpaper ... home mods don't cost much at all even if you don't have the material and with all home mods you could probably decrease your PSI to 500 or below if you do it right. I'v heard some people got down to 350 .. but im not so sure about that ..
Goodluck on your project