there are basically 2 types of superchargers, roots and centrifugal, and also the screw-type which is a derivative of the roots type.
I have the BBK kit which uses an Eaton (roots) M62 blower unit. The kit was about $2800 and installation was performed by myself and my mechanic. It works really well in all conditions. Torque and hp gains are fantastic, and I have plenty of low end grunt. The drawback is there's no easy way to intercool a roots-type blower.
There's the whipple charger that I think is through kenne-bell. Don't know much about it, don't know if it's still available.
There are the Paxton and Vortech blowers which I hear both + and - things about. These are centrifugal, and tend to produce power at higher RPMs, so don't help as much with grunt. You can get new or used kits for cheaper than the BBK kit though.
You can also custom fab your own Eaton setup for about half the cost of the kit if you're really mechanically inclined and have access to a good, cheap machine shop.
I love my BBK kit. My 0-60 is about 6.7 or 6.8 and my 1/4 mile is about 15.3-15.5. It's from what I hear one of the most reliable setups, and I've had it for about 15k miles without a single problem.
