My completly stock 1980 280ZX w/ automatic tranny, t-tops, power windows and mirrors,A/C,CD changer and head unit, r180 rearend, lots of rust, with no driver, no fuel, and no spare tire, no jack or tools weighs around 2700 pounds. The extra turbo stuff and R200 rearend shouldnt weigh more than 100 pounds, So a turbo 280ZX weighs around 2800.
I think that number means thats the most it should weigh with people, fuel and cargo.
I have an 83 280zxt with some mods. I took her over to VT where they leave a scale on all the time and weighed her for grins. The scale was accurate to 20 lbs and weighed me perfectly at 200 lbs. This weight was obtained with the following mods and the spare tire and tools in the car and 1/2 tank of gas. I have weighed each bumper and mounts at about 35 lbs so losing them would net another 70 lbs loss. I estimate that the spare and tools weigh around 40 lbs.
85 CRX seats - much lighter and more comfortable than stock seats
Cruise Control - gone
Vacuum Pump - gone
Headlight Washers - gone
AC - gone
Stock Stereo - replaced
Auto Trans - replaced with manual na 5 speed (probably weighs about the same)
300zx ECCS system
2900 lbs stock?
2760 lbs now.
Possibly 2650 with aftermaket bumper covers and no spare/tools.
Of course, the weight will go up again if I ever get that darn intercooler and wider aftermarket wheels and the darn engine/turbo weigh as much as a V-8. My dream Z would have the new pathfinder/maxima/350z V-6 which weighs around 150lbs less and puts out 240-260hp.