I have a isspro pyrometer and boost gauge in my 300SD (yeah..its a diesel )
Anyway...
The ISSPRO pyro is REALLY nice, responds quickly, and comes with really nice wires and probes and everything.
The ISSPRO boost gauge is not GREAT but it works pretty well. I have the high visibility series as my car isnt a 'pimp sled', its just a tweaker
The boost gauge makes buzzing sounds while the turbo is spooling up (such as in lag times). The buzzing is the cylinders (would be my guess).

I will be posting some info over on the diesel forum if anyone is intersted in seeing pictures, hearing how it works, etc.

My pyro is pre-turbo and I wouldnt recommend post...