Cost for Supercharger plus Install

You might be better off getting the parts your self, shops usally have mark up when they get the parts for you. Shop around and see where you can get the best deal on parts and just have them do the install. Maybe thats what your allready doing, I don't know, It just sounded like they were getting you the parts and the whole shebang.

Definitely check around more - it won't hurt. Most supercharger manufacturers estimate around 8 hours for an install, so say its actually 12 hours - that means the shop is charging you $100/hour. Sounds high to me.

As far as parts go, some shops will charge more for labor if you bring your own parts, so it may or may not save you money. Other shops will have some weird connections where they can get the parts very cheap. When I was shopping around for my Borla catback on my old V6 mustang, the list price was like $750. I got quotes from shops from $525 installed all the way up to $975 before install.

Just install it yourself! If you're somewhat mechanically inclined, you should be able to install it yourself. Thats what i'm planning on doing. saving $1200, seems worth it to me.