Which coolant to use?

[professorman]

Originally Posted by jakeru

This seemingly new aftermarket product, "G40 Zerex" appears to be a match to the genuine Porsche coolant, which I noticed was available at O'Reiley auto parts in the US.
As it's diluted by being pre-mixed 50/50, and costs $22/gallon, though, it's not much of a cost savings over genuine Porsche coolant.
Antifreeze/Coolant Zerex G40-50/50 - Engine Coolant/Anti-Freeze | O'Reilly Auto Parts

I use G40 Zerex concentrate and mix with distilled water. I buy concentrate from NAPA.