Hey! Looks like you got quite a few great recommendations already. I wanted to post a few more for others around the area that may be interested.
A short drive down to Atlanta brings you to Autohaus Social. They are an APR dealer and the facility is really something else. You gotta go, even if it's just to check out the lounge area.
Another great shop slightly west in Dallas, GA is Tune My Euro (AARodriguez). They are also an APR dealer and great folks.
Eurofed was mentioned, and is has opened another new shop in Buckhead, and also are soon to open one at Decatur Square.
Solo Motosports is recommended by many members of ATLMK7.
Autobhan performance only recieves great praise when spoken of.
Eurotech is also a very well respected shop, and close in proximity to you.
Sorry to anyone I could have missed, that is the list off the top of my head.
Also, for anyone that hasn't found us, this is my shameless plug to join
ATLMK7 on Facebook.