DMV installers of amp and sub in 2008 E60?
 

I am looking for a professional and great installation of a amp (using a logic 7 harness) and a sub-woofer in a 2008 E60 in the DC, Maryland, Virginia area. I actually went to Best Buy to inquire about installation, and there were completely no help (not trying to bash Best Buy installers at all). I figure this would be the perfect reference for this issue. Any ideas would be helpful.

Thanks