Originally Posted by mototrmpt

There seems to be a reason it's tough to shift smoothly in the Z and the culprit seems to be the clutch helper spring. In Nissan's effort to make the clutch pedal easier to push, they took away all feel for clutch engagement point. Many have solved this annoyance by disengaging the helper spring or replacing the OEM helper spring with a lighter spring. I've replaced my OEM spring with a lighter spring and my shifting has dramatically smoothed out. I had even better feel without the spring at all, but I preferred to keep the clutch mechanism as fully intact as possible. Here's a link discussing one of the best and cheapest mods available.

Clutch pedal too soft/no feel? Remove the helper spring!