Only option is to change out the spring. Or you can take it out completely but then the clutch pedal will have a lot of play sense there is no longer any tension. If you do either of these changes and do not like it.
Then you can get this
370Z & G37 AFP Clutch Pedal Assemblies - *RJM Performance.com
This will allow you to adjust it more to your liking. My bet is for you to save up those pennies and go this route. Cuz I doubt the first two options will fix the issue you are having. Check out our vendors that offer this product to get a better deal.