Are you wanting facts in general about the 84-89 or do you want to actually know the different weights and such of 84, 85, 86, etc? Hp and torque didn't really change and weight only increased as each model year came. In general a 300zx can weight 3000-3250lbs.
I don't believe I've ever seen a charted list of weights of the different models per year for weight. What I can tell you is that the 84 was the lightest year and as I mentioned before they only got heavier. Of course non turbos weight less than turbos and the 2+2 weights more than either of them. The SF was the lightest model being that it didn't have power windows, locks, etc but I believe these were only offered on Canada and were not produced as much. The GL is your basic 300zx with the GLL having a few more extra stuff and also being heavier. Honestly the weight difference from year to year wasn't that big. For instance a 84 300zx non turbo coupe GL vs a 86 300zx non turbo coupe GL probably has only a difference in weight of less than 30lbs if that. Can you be more specific on what what you want or are you looking for a charted list of all the weights? Like I mentioned I don't think there is a breakdown of all the weights but you could sure start one. Even if you can't take your car to a scale to weight it an easy way to get it is to take the GVWR on the door jam as a base. Then on the inside of the console lid there is some charts that says what the max weight the car can hold for passengers and luggage. Take that number and subtract from the GVWR and you have the weight of your car. The GVWR is the weight of the vechicle plus it's max load it can hold, luckily nissan supplied us with the max weight the car can hold so you just subtract the two numbers. My 84 coupe n/a automatic comes in at 3090lbs both using the above method and using a scale at the track.