The doors on my 1994 Z34 would not open. The handles won't catch to open the door. Has any replaced them? How hard is it?

They are very simple to change. If the lever on the handle itself that engages the rod hasn't broke, the rod itself may be bent. That you can straighten out, and not have to replace anything.

They are real easy to change.You will not find any used ones,the ones in auto salvage yards are gone and most auto slvage yards are crushing the older vehicles due to price of crush these days.