I could tell ya how much it costs to install and tune a bimmer SC, but it'd probably make you want to grab some KY. lol
Yeah, that price does suck (especially when you can buy colder plugs for around 7 bucks a plug), but it's part of their gamble for installing and warrantying a supercharger. It would be kinda nice to know that if the cog belt comes loose (like it's prone to) and manages to shread, you'd just have to take it them and they'd have to fix it. But for that kind of money, I'd just do the install myself and pay more attention to any weird noises and periodically check things out to make sure nothing's wrong.
(I hate condoning a dealership's high prices, BTW.)