The rear shocks on the 280zx are obscenely easy to replace. I recently replaced mine with a set of KYB gas-adjusts. They came with all the boots and bushings needed. My car has custom coilovers front and rear so I can't really testify as to stiffness compared to stock. I was looking for a quality performance shock, and I couldn't afford Tokicos. I can tell you that Gabriels are very soft, wear out quickly, borderline pathetic.