Mate, I agree with everything you said but please read our comments properly as we did not suggest all 33gtrs below certain value (and at the time I was buying is around 25k, 1yr+ ago) are lemon but chances of getting a lemon is higher (and a lot of cases, owners of those cars dont know anything about the car and are cutting corners). I'm saying that because when I was hunting for mine, I had a look at 5 cars in QLD and out of the 5, 3 are crap (condition not very good or owner doesnt know anything about the car from talking to them), 1 is so-so and the other one is the one I got.
Like Terry said, do all the checks you need and talk to the owner. Normally you'll be able to pick up useful info by just speaking with them.
I've seen that on carsale before and it does look really good for someone that wants all work done. I'd definitely give that a go.