As I was shooting some indoor shots with a home-made lightbox I shot these jellybeans as a test for this thread. They were shot with the Pentax K20d in all manual mode, at F22, 1/15 second, 400iso, and 200mm. Using a Tamron 28-200mm zoom. The camera was on a tripod for these of course, tripped with a wireless remote and the only change made was to shoot one with SR on and one with it off. No photoshop was done other than to downsize and convert to jpg.

Here is SR on...



And SR off



Hope this helps, although I may be missing something in the discussion that makes this test irrelevant. I do believe I see a loss in the saturation of colours with the SR on, it's very slight but I don't believe I'm imagining it. Actually with the SR off the entire shot seems just slightly lighter. Actually with the SR off the lighting in the shot seems just a fraction brighter.