for all the parts u need for the conversaion - it should cost around 500 bucks. u will need most turbo parts - ecu, injectors, manifold, turbo, lines, dump pipe, front pipe, intercooler, n also u will need to upgrade ur fuel pump..and then theres the cost of labour - im not too sure exactly how much thatll cost - everyplace is different, but make sure u shop around for a good workshop that actually knows about skylines.
hope that helps you out mate.