I used Stanadyne consistently in my '98.5 w/Diesel Dynamic stage 2's for 40,000K. When it started loping they were removed for pop tests. The tips of all six were pretty dirty w/carbon. That truck didn't get enough hard miles. Maybe just clean fuel and real usage as designed is the best "treatment".Here is a great example for you. Both my friend and i changed our injectors around the 150000 mark. I had been running diesel service and he was running stanadyne. You were lucky to be able to see the small holes in my tips and his looked like they had never been used. Needless to say i am now very loyal to stanadyne!
I thought the XPD wasn't for winter. I don't think it has anti-gel chemicals in it, so I bought the Power Service stuff for winter.