The grille that I have was actually on my car already when I purchased it. It was sent out to a shop by dealership, and then sat in their showroom with the grille on it as a new car.
They tried to charge me $699 for it, but I wouldn't budge and this was the only car at the dealership that I wanted (it was the only black SL hatch without the convience package).
They finally threw it in for $100 when I told them to send the car back to the shop and have the grille removed and not charge me for it. I've tried to find out what shop it was sent to so that I call them and see where to buy the grille (for others that are interested), but they have no clue and everytime I call down there I speak to someone else who tells me they'll find out but then never calls me back.
However, it appears to be the exact same grille as this one that I've been seeing on eBay:
http://cgi.ebay.com/ebaymotors...ZWDVW
I know that people often question the quality of these grilles, but I have to say that it's really not bad. The only complaint that I have is that the metal already seems to be tarnishing slightly, but to be fair I do drive 160 miles a day and haven't tried to polish or maintain it at all.
For installation, the factory top grille is completely removed and replaced by this one (there are brackets for the top and it screws directly to the bumper on the bottom) and the lower (bumper) grille is an "overlay", which attaches to the factory grille with long bolts and clamps that hook onto the back of the factory grille.
You can see pics in this thread:
zerothread/296179
Hope that helps!