I have a good mix of Dex in mine, running a 180* thermo, and Mine rarely hits 210* Usually closer to the 200* mark. Mind you it will get closer to the 210 point during the hot summer months if it just sits, but out on the highway it goes back toward the lower 200*s.

Before you go crazy over me not having the mods to support the 180, I don't care. Car runs perfect, checked with a GM Scantool from the shop. I run the 180 because I don't like the higher temps during the summer months, keep in mind avg 105+/- in Oklahoma in the summer, she needs to be cooler. During the cooler months I just start her up and let her idle while I get ready (perks of having a closed garage).