Well today was a somewhat progressive day. I met my engineer for the first time and gained quite a lot of information.
It turns out using a jap spec engine is fine as long as I used the aussie ECU (at the time of testing) and in total the engineering costs wont be all that much (about $3-5k). Some may think that this is pretty expensive, but it means that the car will be much safer and stronger as a result. Cant argue with more safety can you? It also turns out that the standard fuel talk for the westfield is pretty dodge and I can get a much safer one made locally that can house the RX8 fuel pump assembly.
I've also spoken to option 1 garage again who quoted me $4.5k for the RX8 engine, loom, ecu and gearbox. I've gotten them to include the full driveshaft, fuel pump assembly, full wiring loom from the car including fuse boxes/relays/ignition components from the steering column as well as the clutch slave/master. In total for $5k delivered with an engine check, bargain!
On a sader note, I've had no calls yet for the silvia and it's only been clicked on 108 times in a week. So I've dropped the price a little in an attempt to get some bites. Go you good thing!!