Choice!!
Not sure that a Mazda 6 is larger than the current Falcon, but it is a big car. I think that size car is more where people are heading, with a decent build quality and much better spec for your money over the Aussie cars. As we were saying in another thread recently, you don't get much for your money on a car from Australia.
When does the ST arrive? I'd love to see it at a track day if you are interested in that sort of thing? You'd want to run it in and put a few k's on it first no doubt, but the reviews of them on the track looked like a huge amount of fun!