Suggestion... before you buy anything, try the stock mic clip that comes with the mics. That's why they are there. I've used them, and I don't notice any noise. Once, when a wookie tripped over my stand, I got a low frequency spike, but I'm not positive that the standard shock mount would have prevented that.
Try it a couple of nights for the opening act... if it works, or doesn't, you aren't out any money.