Morepower,
I have been using Evans NPG+ for 22K miles. You should have no seal issues. Here is an exert from Evan's website.
"2001 Dodge Ram 2500 Pickup -
245 HP 5. 9L Cummins Diesel Engine.
The engine in this Dodge Ram is a 5. 9 Liter, 245 Horse Power, Cummins Diesel. It was modified with a Banks Turbo kit and went straight to Evans NPG yielding a 5% increase in fuel mileage. Owned by our own chief diesel tech, he expects greater performance following further optimization to engine and transmission components. "
The engine will run cooler in the winter and run cooler when you turn up the power. A few others have noticed the heater works quicker in the winter with Evans. I know of about 60 Power Strokes and just a handful of Duramaxs & 6. 5s running NPG+. The guys that are towing heavy with the 6. 5s like the cooling ability. One negative with Evans would be the radiator adding heat to the trans cooler in the summer.
Make sure when you change over to remove all of the old coolant. Flush your engine a couple times.