I hope they have bindings for that price. You can still find older models brand new and flat for that price. Here is a 172 if you were considering going smaller just as an example: http://www.sportsliquidator.com/item.asp?id=2637
I am 6'1" and 210#s and swear by 8000s in a 178cm. At 5'9" you probably could go either way depending upon preferences, ability, desired use, and weight. If anything I would wonder if those 6s were just a tad small but that is the problem with ski sizing... often times you need an intermediate between the available sizes that is not offered.
They are a rocking ski but wikked different feel from the 6*. I switched from a volkl P50 to a Dyna8000 and loved it. But I switched styles from railing groomers and muscling everything to finessing natural snow. If you are going for the ideal three ski quiver, a 6* and an 8000 would be my top choices for groomer and everyday ski. Just need a pow board and your line up would be complete