well it depends on your aspects but you would want a complete Rb25
RB25 (series 1 or 2) 2 has vct! ensure it comes with manifold, wiring loom and ecu. that will get you out of trouble. While its out change heater hoses and put in a new rear main seal and things like that to save you the trouble later when its running.
the rest of the cost will come from things like wiring under the dash as its slightly different etc....if you are not running with a gear box change you could prob pull it in for 3k or so