The Lexus look has change quite a bit over the years. Looks like they have gone from a more sharp design to more curved clean lines through the body. The new generation also looks a bit bigger as well. At least they haven't strayed too far from the original look.
I know that the design has changed quite a bit over the years, but in the photo above the vehicles look eerily similar. It also might be because the major design shift for Infiniti happened after 2006.