An EZ will quiet down the motor also,, because of the timing it does with the injection pump.
I noticed my truck,, even though it is a COMP (Big Brother of the EZ) the motor went from a "Knock-Knock-Knock on the highway, to a very smooth Purrr. Sounds much more like a 12V now (but not very close)
MerricNJr
P. S. Not to mention the extra horsepower (55hp?) and ~1MPG the box has to offer