Blue - What did you mean by checking my messages? I'm obviously missing some other feature on this site. I have a Vortech S-Trim supercharger and 3.73 gears. From all I've read 3.73's are the gears to go with if you have or plan to get a supercharger. In terms of your question about type of supercharger there are two main design's for a supercharger, a Roots style and a Centrifugal. Roots makes more torque than hp and a Centrifugal does the reverse, more hp than torque. Check this website out
http://www.motorsportsdigest.com/tech.htm it will explain the different brands and designs much better than I can. This site heavily influenced my decision to go with a Centrifugal and Vortech supercharger.