Somewhat off topic I know but this very discussion is one reason (among many) I do not like the 2006 - on DTS model from Cadillac. In order to get the car you wanted you had to be very careful to order or to find one with the right option packages or order it correctly.
In the previous incarnation of the full size model you had the DeVille, DHS, and DTS. With each you knew what you were getting. And then in 2006, just as GM had previously done when it applied the up level name to all models in a range (think Impala, Le Mans, Grand Prix, and Bonneville), it renamed all cars DTS thus bringing the "cache" of the DTS to all versions of the car but making it harder to know what you were getting. Whether it was a 'real' DTS (which up to 2005 included the electronic suspension, heated/cooled massaging bucket seats, 300/292HP NS, larger wheels, configurable analog/digital instrument panel, fog lights, etc.) or a garden variety DeVille with the DTS model name applied. And as another replied here GM confused things by alternating from one model year to the next what options packages you had to select what you had to order to get the performance package. It alternated what was included with the Platinum models in terms of the performance package. From year to your you had to figure if the Platinum model included the performance package or not with the uprated engine and suspension so you could get the combination of luxury features with the performance features as you could in a 2004/5 DTS with the Premium Luxury Package. Yes, it can be figured out by looking at past brochures (which I kept as I was considering replacing the '04 DTS) and other sources of information) but it was so much easier when Cadillac let you and others know what you had but the discrete DTS or DHS badge on the back and the subtle alteration of wheels and trim on the outside.
I am all for being able to order options to configure a car the way you like it, but options usually don't count for a lot when it comes time to trade so if you want the uplevel it sometimes nice if there is model that says it all as Cadillac did with the original STS, DTS, and ETC.
And, of course, there was the loss of "White Lightning". Replaced by White Diamond in 2008. Tragedy.