I own a Dodge Ram 2000 (model 2500) with a cummins turbo diesel
engine.  I am a contractor who does quite a few estimates so when I
pull up to a customers house the noise is sometimes disturbing.

Anyway, my question is this:  Is ther anyway to quiet the engine down
(specialty muffler, etc.??) without decreasing the performance
significantly?  Would like it to sound like one of the newer diesels.

Thanks

I think that it is going to be a lot more complicated than bolting on
a specialist muffler. In 2003, Cummins redesigned the fuel system
using the Bosch high pressure common rail system, enabling pilot
injection before the main injection.  This reduces the spike in
combustion pressure for dramatically quieter combustion. In 2004
Cummins added rubber isolators for the valve cover bolts and further
reduced the noise at idle by changes to pilot injection. At about this
time they also increased the exhaust bore size to 4 inches to help the
beast breathe. I would bet that if there was an easier way to reduce
noise Cummins would have taken it. It looks like your options may be
to park down the street or trade up to a 2004 model.

A diesel is gonna sound like a diesel no matter what you do it, I
expect. Even Mercedes diesels sound "rattly."