i own a r32 gts-t 4door still with the rb20det motor. not very familiar with kw's though my car made 310 rear wheel hp on 14psi. all i have is a 3 inch exhaust hi flow cat, 500hp in-tank fuel pump, front mount intercooler, turbosmart boost controller and got my turbo hi flowed and changed to bigger steel wheels instead of the ceramic standard ones. i was told more power is easily acheiveable cause my injectors have maxed out now running a 98% duty cycle. next would obviously be injectors and management.
but i think maybe i would like to have a play with a gtr conversion...
Hope thats helps you out...