Sydney Tech > Hurlstone > Girraween
Anyways, Sydney Tech probably should beat Hurlstone by more than 2 places considering it doesn't offer certain subjects that Hurlstone does (or so I've heard - e.g: General Maths, Primary Industries, Agriculture, Senior Science) as well as the fact that those aren't the most academically inclined subjects, thus giving Hurlstone a nice leap in terms of rankings over other schools by getting B6's in those compared to more 'rigorous, academic' subjects.
Not jelly or anything, just laying out a fact.