That is pretty high for that z31. I picked my z31 up (picture in signature) from the original owner with right at 90k on it. Mine is a turbo and has the larger T3 over the t25 and has the CLSD. I paid $3500 for mine. I washed it up and detailed a month after buying it, and it placed in the showroom class at the North Carolina Fall Z car show. A z31 turbo has 205 hp and 220 ft lbs of torque stock. They are a few hundred pounds lighter than a z32, so I would say a z31 turbo would eat up a z32 NA in a straight line.
That being said, the real issues on z31s would be changing the timing belt, making sure the Nissan injector recall has been done, and the fuel gauge probably never will work, harhar. I drive mine daily and enjoy it. I get good fuel milage out of it and it comfy.
The z31 turbo motor is also very responsive to boost, so for the price they are asking for that z32, I would say you could have a more reliable, faster, cheaper z31 turbo. Check out z31performance.com to see some sick z31s.
Oh....my vote is for the z31.