Soooo you are trying to save a grand by getting a basically unsuitable turbo which will dictate that you spend at least another 10 grand to get things to deal with it?
To the thread starter, I honestly mean no offence by this but I really think you don't know enough about what you are doing just yet or have the experience to understand what you're getting into.
Comments like this give it away:
I mean, this is a full engine rebuild. It's not getting a couple of bits bolted on. This is a many thousand dollar job.
All that said, you don't sound stupid so probably another few weeks/months of hardcore reading and you should be ready to go. Feel free to keep asking questions but you can get lost for months just on this website as there is a mountain of info here. Also scam some passenger rides in some Skylines with varying levels of power (and ask the owners how much it cost them) to give you an idea of what you really want.
cheers.