they have the ADAM2 regulator to retrofit it so that it is like the digital guns. not really performance improving but will give you better accuracy over a regulator before the gun by maybe 2psi +/-.
the internals that slide into the gun are identical to the internals of the guns pressure knob that you are replacing so no increase or decrease in flow just better control and more accuracy in the indicated pressure but not by a noticable amount.
here is a vid from youtube that shows the installation of the adam2
I use an at the gun diaphragm regulator, not at the wall. My gun is a minijet. I thought if I remove the diaphragm and adjust at the built in unit things would improve.
it will like i said it will give you a better more accurate reading. do a test, if you do buy the adam2, install it and leave your other regulator on. then read the psi on the line regulator and compare it to the adam