Need help with grill..??

Why would you want to use the V6 one? I think there is a probably a difference between the two otherwise they would probably not distinguish between the two.
 
The CDC grille can be found on stage3motorsports.com for 275 which is quite a bit less than the roush, and by looking at them I can't tell the difference. The hardest part of the install is getting the stock grille off, there are two tabs on each side and 4 on the bottom, the top two are easy to get to, but the bottom two on the sides are a pain. Installing the new one is real easy, took about 20 min.
 
Shelby has theirs in Black also (same as the ones on the Shelby GTs). You have to purchase the grille housing and the grille. They sell them as a set for the standard one, but you have to buy them seperate for the black one. Here is a link to the housing/grille combo:
http://www.shelbyperformanceparts.com/ShowItem/100847 Shelby Billet Grille Assembly.aspx

Black Grille:
http://www.shelbyperformanceparts.com/ShowItem/100760 Upper Grille Insert.aspx

Housing: Not on site, the housing is in the PDF catalogue on their site and is part# housing is 8s3z-8200-h.

I purchased these and have yet to install them, waiting for the weather to warm up. The quality seems good. The housing was $104.95 and the grille was $109.95. Not too bad. This housing and grille combo are exactly what comes on the 2008 SGT. Just wanted to throw out another option. Hope this helps.