Elegant,Great question and one a new C7 owner should answer directly. Allow me to add to this issue that if a C6 owner gives you an answer, please consider it in the context that the C7's MSRC is a much improved system, with now two coils inside each shock, giving you not only the fantastic "conversion to full shock firmness" when needed 1/1000 of a second that the C6 had, and also the second/additional coil is wound in reverse, giving each shock much, much quicker "conversion to softness" when desired.
For those who want background, here's some fun videos. The first one is the first MSRC system in the C5, and it is useful in giving a simple explanation/diagrams how MSRC works:
The second video is a 2012 Cadillac ad, just 38 seconds long, and shows a CTS-V versus a Ferrari 458 Italia on the track. Interestingly, if you bought a brand new Ferrari Italian or Audi R8 today, you would get the second generation GM MSRC system, not the third generation system that comes in the StingRay.
I have to see if I can find it, but I seem to remember a slightly different soft-to-hard ranking: The Z51 with MSRC set to the softest setting was the softest ride, followed by the non-Z51 base, followed by the Z51 without MSRC, followed by the remaining Z51 with MSRC setting up to track.Agree fully with what glen e posted above, for the word "taut" is an excellent and accurate term to describe for the ride I just completed in a Z-51 without MSRC. You could also use the words "firm" or "responsive." Compared to my C6 Z06, it is, however, a "pussycat suspension." Compared to a entry level StingRay, it is definitely firmer, and if you live in an area with lousy roads and do not like a firm ride, then the getting the car without the Z-51 suspension is a good idea. What remains to be seen, is a back-to-back test of a standard suspension with a car compared to a Z-51 suspension WITH MSRC!
Going way out on a limb, for we do not have comparative tests, the standard suspension is obviously the softest, with my guessing here, the Z-51 with MSRC being 20% stiffer, and the Z-51 without MSRC being an additional 10% stiffer, and, finally, the C6 Z06 being at least 25% stiffer than the stiffest 2014 StingRay.