Tonight I put a 180 Tstat in our 300C Heritage Edition and it gave me a look at the differences in the coolant systems and what I believe to be another aspect of the gunk aftermath in my MSRT8.
Here's a pic of how the Tstat well looked (with residual "good" coolant) in the H.E. when I removed the stock Tstat...
The coolant is nice and red without any evidence of the white particulates that give it that lighter, milky appearance.
Here's what the Tstat end of the radiator hose looked like (this on the H.E.)...
Looks pretty good. Nice, completely black interior coating. Now compare the above picture to the similar picture I took after changing out the Tstat on the MSRT8.
Quite a difference...!!! It is my guess that the elevated temperatures in the coolant controlled by the stock Tstats, in combination with the gritty particulates circulating in the SRT8 coolant prior to the flush is what resulted in essentially etching away most of the surface coating of black on my SRT8.
I would be interested in other SRT8 owners investigating whether their Tstat housing end of the radiator hose also shows this kind of evidence.