I feel that all the advice on the pumps is a bit misleading.
I use Carter pumps (like the OEM, but improved).
One on the frame, pulling thru a 30-micron filter, and
feeding a 10-micron, and the one on the block as backup
feeding the stock filter, with a 2-micron after that.
>20 PSI at idle, 18 PSI at max pedal.
The key is low restriction - replacing the banjos helps marginal
installations and modded (high HP) systems. Same for bigger lines.
BUT, for a stock system, the OEM pump is fine, as long as it is good.
You can take them apart and burnish the gears for some improvement
if they are scored.
Here is a source for the Carters:
1998-2002 Dodge, Ram 2500 Ram 3500 - Fuel Injection Diesel Parts Selector

They also have the FASS DDRP's for folks who don't believe the above.

 

I replaced the carter yesterday it was a tight spot but not hard to do.They gave me a new air-tech to make up for the carter that was the old style pump.It picked up prime first bump of starter and is running great.Now got to get a fuel pressure gauge and cross my fingers it didn't get my injection pump!

 

I got my lift pump on Advance made it up(thank God because money is tight right now)and gave me the latest Air-Tech available(goes in sideways)and it started first turn.My friend owns the local NAPA store and said that all Air-Tech lift pumps are junk? I will put a FASS or Airdog on when spring comes(And my work situation/$ is better)and farming picks up.Now I'm still getting a slight hesitation at idle.My truck runs fine other than the idle miss at low RPM's any suggestions?