I posted a while back regarding doing something like this. At the time it worked out that getting a full coilover setup from Powertrix,SPL or just getting Tein's was only slightly more expensive by the time you were done.
"The 300ZX Turbo is a dance; it's a song; it's rolling, roaring automotive art. There is no color that doesn't suit it. There is no mood-lifting chemical substance it can't replace." - Automobile Magazine