yeh the 17c has a rating of 400hp in internal form, i made 280hp before converting also at 19psi and full boost was at around 4000rpm. but the tune wasnt as good.
mods are:
gts4rb20
gtr injectors
ems stinger
td06 with tial copy gate
cooler, big breather
pretty small budget, biggest gains were had with opening up the back of the turbo and fitting a big pod. all of this is in an s13 silvia aswell, will post graph soon