He's be at this for awhile the link below is of similar charges some time ago. Wow.
http://www.peninsulaclarion.com/stories/122101/ala_122101ala0050001.shtml
If you hire someone to install it for you, be there while they do it. You'll learn a good deal watching them on this project. Prep before drilling, running wiring, connections, etc. You'll buy a lot more than an install of you're able to watch how they do it.
I made friends with our mechanic...