Well I have factory dual tanks and dual spare tyres. So it can all be done,....... with a small catch. From my understanding, the aussie models have large 2nd tank, I think 80 litres, so their total capacity is 170 litres plus. Where as most others market get the 96 + 45 litres tanks. I presume if you have the 80 litre 2nd tank than the tyre can't be mounted underneath, otherwise its not a problem. With rear 2nd tank and under tyre, the tyre is mounted in a slant / slope, so even though the departure angle is reduced, its only by a small margin, and I found it to be rear bumper saver in actual practice. And lift kit solves all issues for offroading ! 
