[Eibach Springs - Front sits high... *pics*]

You've got the springs installed backwards. Swap them front to back. Had the same issue last year.

[77 280z rough idle after warm up]

I'm having similar symptoms on my recently purchased '77 280Z.  Runs reasonably well when first started, but once it gets a bit warm the idle is a bit wobbly.  Has changing out the ignition module helped anyone?  In addition, it takes it's sweet time getting back down to idle while driving, sometimes as long as 10 seconds....could these two symptoms be related?