Not LA area.. but worth the drive.... i take my stuff to Pacific Audio. They do magazine work and high end diesel performance (PPE). They've been in business for years and are not a fly by night type of place.
Anyways, they're not the cheapest and usually super busy.. but they great work on RV's, boats, custom setups and of course the SMB's.
They just installed a head unit in out rig a few months ago and did a great job. It was a piece of cake for them.
I agree with not going to AL and ED's. The stereo we replaced was installed by those Yahoo's and the job was done so bad, i have Pacific clean it back up.