Sydney option
Hi there,
I have also heard good about the gent at Tristar.
If you are interested in the Sydney option, try Gavin Secombe. From him, you will learn a good understanding of the subject not just a bunch of shortcuts and cheats to get you through.
Also, Gavin recommends a really good homestay accommodation that includes nice home cooked meals so all you have to do in the evening is eat and study.
Hope this information helps.
Good luck.
P.S. I don't work of either of them