npg+ is a different animal
you have to completely drain your water based coolant and replace with npg+. the aux fans trigger at 105C and the thermostat opens at 87C, those are what you probably need to adjust, mainly the thermostat although i think MB temps are already optimum ( i think they want you to modify your system to run hotter). the coolant won't boil off at all which can happen in water based systems. non-water based coolant ideas have been floating around for a long time. the problem is when you lose coolant you have to replace it with the same special liquid...
1993 300e-2.8 - gone now <sigh>
"Do not adjust your mind, it's reality that's malfunctioning"