I'm surprised that no one has mentioned the RJM clutch pedal in this thread. I have a 09 6MT I bought used two years ago and had a hard time getting use to the clutch. I'm 61 years old and have been driving a manual since I was 15 so it wasn't me. I read about the RJM adjustable clutch pedal and immediately ordered one.
Wow! What a transformation. The stock clutch/tranny is wonderful now.
I have no affiliation with RJM, I'm just a customer, a happy one.
What the new pedal does is change the engagement point and spreads the engagement over a longer distance making it more controllable. You can still get jutter if you don't get the revs up but a lot less than the stock clutch pedal.
Now i REALLY LOVE my Z!