Not the CS springs, but I've been running a set of Manzo Performance springs on stock shock for 6 months now. All of those months were Jersey winter/offseason conditions. Just took them off last weekend. Dampening is very good, ride quality is good they havent sagged at all but have settled nicely at 23.5"F and 24"R which is exactly the ride height I am running the STF BC coilovers at. No leaks from the stock shocks.
Springs rates were calculated at approx 205F 175R (both progressive). They are a bit softer than the other widely available options including the ones you've mention. They ride nice and fit the budget well. I bought them with a 1 year warranty on them for $45 shipped for the set off our favorite online auction site. I have seen them for $79 shipped with a lifetime warranty. Not sure why the difference in price other than to hedge a bet that if they fail, the vendor will just ship you a new set. They are painted, but it's thick enough to so far stand up to Jersey salt levels ;at least for one season so far.
In answer to your exact question though; No, your stock struts will start to leak and/or get weak soon after installing a spring that lowers the car that much and being that stiff in rate. I put these on to see how long the stock struts would last on them full expecting to upgrade/ replace them with something else when/if they went to mush.
