well, after looking into it a bit more, i found that the GT4082 is available with a T4 "International" housing, which is a different flange to the regular T4 housing, and the manifold I had chosen was a regular T4 Divided type...
So I stepped things up a little, and went for a GT4088R, with a 0.85 rear...
I'm broke as now, but I just got a raise at work, and paydays only a week away... (And I have enough to get me through till then)
The turbo should arrive early next week, and hopefully will not be too big for me in the short term (it'll be just right in the long term, with future plans including either cams or cam timing adjustments and bigger injectors, aftermarket intake manifold etc as required)
My long term goal for this car has always been to top 500rwhp (by a decent amount, so that I can replicate it on most dyno's in WA, so in other words, 550rwhp at a minimum), and this turbo should be able to do that quite comfortably.... My only real concern is that it may be a little on the big side for the intermediate steps (which I was planning on doing first, until something forced my hand)