One has to consider when comparing a Cruze with the z-link suspension and one without. To my knowledge, the Eco does not have it, while the 1LT, 2LT, and LTZ do have it. I'm not sure about the LS.
Point being, if you buy an eco, not only do you not have the z-linnk suspension, but you also have the "crap for grip" LRR tires, so you can't really blame the reduction in handling ability solely on the lack of the z-link suspension. In fact, it's impossible to do so unless you put the same wheels and tires on both cars.
I haven't read anything that would indicate that the z-link suspension does more than provide additional stability over bumps.