Dempsey Anderson at Evolution Motorsport Engineering has recently come out with a full set of coilovers for our ZR-1's and other cars. I believe these will be a first 1/4 purchase for me. The old shocks and springs will go into storage. He has just completed work for me on a recently purchased 91. He is a great guy to work with and will offer advice/pro and con based on your desires and goals.
http://www.evolution-motorsport.com/
Good luck with the search.