Sorry i didnt see this sooner...
Megscan,
you're in NJ, and if your looking for the right person to protect your cars virginity, who has extensive experience with our late model BMWs you def need to get in touch with Don at Unexpected Creations in Edison. you can google that for contact info, but i'll PM you as well.
heres my story... 2011 328xi, I handed my car over with less than 3000 miles on it to Don with a budget of right around 2k. I had the appalling 6 speaker base stereo. He did a fantastic job. So good i brought the car back to him for more work later. The job is totally stealth, maintains 100% factory functions, is fully reversible with Technics harness, and the sound is simply awesome.
Here was my post install write up.
http://www.e90post.com/forums/showthread.php?t=451762
and i had don do a basic alarm for me too
http://www.e90post.com/forums/showthread.php?t=457584