Both are supposed to be very advanced struts, with the Ohlins allow adjustability. I would be very interested to hear any first-hand experience that compares them.
Z28 is an unsung and underappreciated supercar, but nevertheless a supercar. If the need of civilized road manner calls for coilovers, I would want something that is at least comparable to the technology and build quality of Multimatic DSSV's from the factory.