This is a simple spacer lift. The stock shocks and springs are being used but at least in the front b/c you're adding 2 inches of spacer it just compresses the spring a little more, or at least it seems to! I know it was harder to get back in b/c of the spacers! Here again, just my personal opinion but it made my Jeep at least SEEM like it was a little firmer up front. But it could be all in my head...wouldn't be the 1st time!
Is this a spring or spacer kit? I don't see how a spacer kit can firm up anything if the stock springs and shocks are still being used. The spring rate isn't changing nor is the shock rate.