Australian Tour Edition
The bonus tracks are:
12 We Are Young (feat. Janelle Monáe) [Acoustic]
13 Carry On [Acoustic]
14 Why Am I the One [Acoustic]
15 We Are Young [Alvin Risk Remix]
The Australian Tour Version has four bonus tracks: three acoustic versions and one remix. This edition has different album artwork and is just under $20.
Japan CD First Press Limited Edition
The bonus tracks are:
12 Carry On [Acoustic]
13 Why Am I the One [Acoustic]
14 We Are Young [Alvin Risk Remix]
15 We Are Young [Betatrax Remix]
The Japan Limited has the same cover art as the standard version. It has two acoustic tracks and two "We Are Young" remixes. Apparently, it is a limited version; however, it is still available new at just over $20, more than a year after its release.
Bottom line: The Australian Tour Version is a better buy if you want the different album cover and more acoustic versions. The Japan CD is only better if you prefer the Betatrax version of We Are Young over the acoustic version and if you want a "Limited" first pressing.
The Australian version is available at amazon.co.uk
The Japan version is available at yesasia.com