Hi jordon, go 3 inch exhaust, use a rb20 wastegate actuator,maybe find a hi flow op6 neo turbo or a stock neo(rb25) wind it up to 12-14 psi should get you 200-220 kw at the wheels. more for the high flow but watch your fuel injectors, they woud be maxed out.
otherwise the usual z32 airflow meter, bigger injectors and a remap with a decent turbo will get you 240- 250 kw atw.