Autozone. I looked at Napa and another store (maybe advance?) but they didn't have any.
It's made by "Cowles Custom"... comes in a roll with plenty of it for $10-11 bucks. You could probably paint it black if you don't want chrome. I think Napa may carry some in black, but not for sure on that.
Here's a couple of pics of the install. The bumper was not modified in any way to prevent me from going back to stock.
Stock grille removed:
Painters tape under the two tabs that you will dremel out.
Just make a tiny ass slit in each one. Make sure not to get it too big, or else the grille tabs would easily slide out. Also be sure to make the slit down low like on the other tabs, or else the bottom of the grille might not sit flush with the bumper.
Then cut all the tabs off the new V6 grille EXCEPT for the two that line up with the tabs you dremeled out on the GT bumper. Also do NOT cut the tabs on the top of the grille that have holes in them. Those help secure the top portion of the grille when you put the radiator cover back on.
^Pic of grille with the tabs removed.
Then just put it on! Work the two tabs in your small slots with your fingers. Don't push on the actual grille part too hard when doing this, or it might crack.
I want to eventually make some brackets or something to hold the top portion of the grille to the car, but it's fine for now. It may be a little flimsy on the sides, but not "flapping with the wind" bad. Nobody's going to push on it anyway.
Sorry for the craptastic iphone pics.