I have a challenge for the distilled water faithful--find me one, just one, single repair shop or dealership who uses distilled water. It's much more "professional mechanic" than backyard.
Modern coolant is good enough that it doesn't make much difference. Now...distilled is better, and the notion that tap water is better is absurd. As is the idea that a 1.4 bar rad cap is an upgrade in any way, but hopefully we won't go there again.