If you want a Supercharger for show, get the P1.
If you want good performance and reasonable price in the 600-900rwhp range, go with the D1.
If you're insane (or an all-out race car) and price is no object, go with the F1 or better.
The new i1 (
http://www.procharger.com/i-1supercharger.shtml) is very interesting.
Or you can do like I did, and do a D1 with a wastegate and boost controller, and you can do basically the same thing the i1 does. Though it will be interesting to see how the i1 does.
Padre