How Does New Model Affect Used Car Price?

I am looking at purchasing a used Infiniti FX35... Somewhere in the 2 year old range with less than 20k miles. With the equipment I want they are going for the very low 30's from dealers.

Given Infiniti will release the 2009 updated model toward the end of summer 2008, what price impact would the new model have on used models of the previous style?