Everything I know to be different is the rear wing, the wheels, the brembos are black instead of gold, the sunroof, the center console is black instead of silver, the leather interior, the authentic v-limited lip comes stock on the front, and there is much more sound deading material throughout the car to make it more "comfortable" and less rugged like all the other STi's...
There may be something a little different in the struts/springs as well to add to the whole "comfort" factor but I can't remember off the top of my head.
Basically as previously stated, its all asthetics, whereas the performance is most likely worse than other sti's b/c of all the added stuff (sunroof and sound deading material mostly).
hope this helps! I know there is something i'm missing..