dsmlink, a big fmic, bigger injectors, stronger clutch set up.... then 20+ psi would be no problem... Hell 25-30 on race gas depending your current motors condition ( arps and a better h.g. would help at these levels especially.) But even on pump gas 22-23 psi with a carefully watched; meticulous tune would work. Its better not to throw out a random number like saying you want to run 17-18psi, instead make goals such as ' you want x amount of hp, or you want to run xx.xx time in the 1/4' Because a random boost number doesnt determine anything to be honest, and 17psi isnt worth it on that turbo if you were running it that low ( low to me.lol)
but thats like saying i dont want to make that much power on this set up and in which case you should just get a evo3 16g for less power and quicker spool.
Other wise get your supporting mods and max that thing out.
Just my 2cents.