I am interested in the new "Ruf" Kompressor (supercharger)conversion
for the Porsche 911 S (3.8 litre) 997 body style. How does it work? Is
 overheating a problem.  I already have the factory sport exhaust. How
much better will the new conversion sound?

Its centrifugal supercharger is mechanically driven. The advantage of
the mechanical supercharger over a turbocharged one is the high and
constantly rising torque already at low rpm, yet it does not achieve
such a high compression ratio towards the end of the scale.

Overheating is generally not a problem with Ruf cars, since each motor
is tested thoroughly and individually set up. Moreover, the
intercoolers are cooled by an additional watercooler at the front
spoiler. Last but not least, Ruf does grant a 2 year/24.000 miles
warranty on the engine.

I would not expect too much of improvement concerning the sound,
despite the new catalytic converters. The factory sport exhaust is
already pretty loud. But the engine's caracteristics become more
race-like and aggressive, and this will of course reflect in the
sound.