Hey mate, been reading through your 32 GTR build that was a great read and loved the pictures!
In regards to the project car being street legal and registered, i think your going to come across a lot of difficulties with the QLD government as i'm sure you know. I'm no expert in this field, but have you considered buying another car something like a ute or wagon (wagon would probably be a better idea for the twins) and a trailer and just doing what most people do with track cars and tow it around? I can understand how great it would be to have your track car also a daily drive, but unfortunately there are a lot of hoops you have to go through to make that possible.
Whatever you do, goodluck! Once i'm off these silly green p's i plan on getting myself a pearl white S15. Absolutely love the shape of the S chassis and the range of parts and mods you can do to them is massive, not to mention SR20DET parts are reasonably cheap.