Unfortunately they are way more expensive. FYI a new X5 50i will set you back A$133,400 while even the cheapest X5 (the 30d, a single turbo diesel not sold in the US) will set you back A$92,100. These prices are before any options or any on-road costs such as government taxes, registration etc. That's why second-hand X5s are much more expensive. And, all this despite the fact that the Aussie dollar is close to parity with the US dollar.