This has been discussed here many times in the past. The short answer: yes, however, there is a catch and that's when I get into the long answer. Not only will you need a new grill, however you'll also need a new bumper, and several other parts as well (from the 2008 MY car) to fit your pre-2008 model. Long story short: It's not worth it unless A. You have a lot of money. B. You have a lot of time. C. You REALLY want your car to look like a "newer" STS.
I did my fare share of mods to my previous cars/trucks, however, this is one very costly mod.
You got it !Thanks, after doing some research your right I did find this topic talked about and it does look like to much time and money, i'll just go with a mesh grill I think, thanks for the reply