I am no expert but I would imagine that your rather unique and enviable purchase has much much more in common with the 240K, as the 240K was the KGC10's immediate successor. Apparently the sedan version (not the twin cam s20 GTR) was exported to some wierd places like the Netherlands with the L24 engine -which made then unique as the car was never sold in Japan with more than 2 litres. As with the 240K, this generation of Skylines had IRS at the back if a 6 and rear leafs and a shorter body structure forward of the bonnet if a 4 cylinder.
I have a road test or two of the 240K and Wheels Magazine mentioned that the setup, whilst similar on paper to the 240Z was quite different, and superior in some ways too, such as tail squat under acceleration.
I know this is not much to go on, but I hope it helps.
Having a L28 in your car makes sense as the S20 motor, whilst looking and sounding more exotic, probably is less robust, costs heaps to repair and parts would be mega expensive and hard to get - especially in sunny Perth! Just make sure you drive it on sparsely trafficked roads - you don't want some retard hitting you (touch wood), what with panels not exactly being thick on the ground.
Sadly I would imagine there would be very little detailed technical info on these cars as they were not widely exported. Internet browser transaltion software will become a close friend, unless you read Japaneseor have a friend who does
If you can post a piccie or two - that would be great.