Update on the tires.
The stock Dunlop SP Sport Symmetrical 5000 had dismal online reviews; averaging 2.5 out of 5 stars.
Being a Michelin guy, I looked at those first.
1) The Michelin Defender, a 80,000 mile tire that I use on my other vehicles, were not available in 225/50R18.
2) The Michelin Premier A/S, a 60,000 mile tire that had excellent ride quality reviews, was having significant premature tire wear feedback. This was confirmed by both the local Belle Tire and Discount Tire.
3) The Michelin Pilot Sport A/S 3+ is a 45,000 mile tire that while getting excellent ride quality reviews, was, well, only a 45,000 mile tire.
So, more internet research. A name that kept popping up with excellent reviews was a brand that I had never used before. It was the Yokohama Avid Ascend GT. It is a 65,000 mile tire which held it's own against the Michelin Premier A/S in a tire test published by TireRack.com. After additional shopping and research I came across the Yokohama YK740 GTX which is a 60,000 mile tire that is purportedly very similar to the Yokohama Avid Ascend GT. It had excellent reviews including one from a CHR owner in California. The YK740 GTX was slightly less expensive than the Avid Ascend GT, had a $75 rebate that the Avid Ascend GT did not have, and the dealer offered $200 for the OEM Dunlops. After about 150 miles of driving on the YK740 GTX I can report that I have a tire that, while not a Michelin, does a very nice job smoothing out the ride on the CHR. I am finally happy with the ride quality of the CHR.