i installed my supercharger and got everything running correctly, but it just seems that it is not performing as is should. i can definitely feel a power increase, but it is not quite what i had expected. do you guys out there who have superchargers know if this is normal? from reading what superchargers produce hp-wise, i was expecting at least a boost of 100 hp or so. feels like maybe a 30-40 hp gain.

 

The biggest claim I've seen from a supercharger kit on a 318 was 70-some HP.

 

Is your tb hat plastic or metal? Some of the older Powerdyne kits had plastic hats that tended to crack & leak. Make sure any connections are tight and not leaking though thats more of an issue with an intercooler.
If your hearing belt squeal when going WOT then your loosing boost.
How many psi boost are you seeing? What is your air to fuel ratio when in boost?

Most 5.2 4x4 owners say similar things about not getting the hp they expected. If everything is good, I agree with Jason, 70ish rwhp can be expected, if you have issues, much less.