The problem with these other versions of Top Gear, not just the Aussie one, is that they should've found people with their own chemistry, instead of trying to find people with similar personalities as the originals. Instead, we get the older quipping guy, the young 'hip' short one, and a middle aged guy who 'shouldn't be cool, but is.
The US one would've probably lasted a lot longer with perhaps Jay Leno as the host.
I watched a subbed version of the Russian one a few months back and it was absoloutely woeful.