whats up with that empty spot in the middle that makes it jerk?

It's called the clutch helper spring... I think Nissan thinks that it helps people who don't know how to drive MT. Why they would cater an MT vehicle feature to people that don't know how to drive MT, I have no idea.

There is a lighter spring available (search the forum for clutch helper spring and LMBmike's thread selling them). The best solution, however, IMO is the RJM clutch pedal assembly. It has linear movement with no spring or sudden release action in the pedal travel like the OEM pedal assembly.