The no grey import makes it hard as most newer RWD cars that aren't badged Holden or Ford are imports from Japan.
The older Skylines are very clean and relyable (I had an R28 style '83) but the 3.0L R31 model is OK and you'll have $$ spare, or you could get lucky and find an Aussie plated R32 GTSt but they are classed as collectors items so will eat up most of your cash.
Gen4 RX7's are great cars, the issues with rotaries only come when people start tinkering with them, that are actually quite reliable stock but do guzzle the juice!!! Something to think about these days...
S14 200SX would be perfect but hard to find one that is stock and not trashed, but they are out there, my old neighbour in Adelaide had one and it is sweet... you just have to be paitient when looking and inspect the car well... S13s (180sx and silvia) are all imports...
There are a few well modified old Celicas and Supras that would be great for you to play with too, visit toymods and chat to a few of those boys for some ideas (or talk to Dave ). The old Supras (pre '93) are not actually that heavy as they did not have as much in the way of electronics and mod cons...
But my personal choice would be to stick with the Stivo as your daily driver and grab yourself an old Datsan!!! It may sound stupid but an old 180B/stanza/sunny SSS is a brilliant light RWD car and easy to work with and modify. Or a Datto 1600, Escort or something of that ilk will give you much more enjoyment as they were designed as Rally winners and buily to drive sideways in...
Check out the Trading Post and see what is available and be open minded about it... It all depends on your intended purpose...