I don't know how to explain or a word to use, but here is a situation...

I only drove my car 4000 miles.

when I shift from 1st to 2nd, it takes for a while the rpm needle comes down. I shift at 3000 rpm, so when I shift like any other cars M3 or even MAzda6, the car rattles because I took off the clutch soon. It gets worse if I shift 1st to 3rd direclty(1st 4000rpm to 3rd 2000ish I have to wait about 1.5 sec to match up the rpm to match 3rd gear)

Does 350z's clutch is too sensitive? or do I just take off the clutch too fast? OR SOMETHING WRONG WITH my car...

I'm not expecting formula car or somethin, but I've never had experience like this with E46 M3 or Mazda6...

 

The Z has no clutch delay, so engagement is rough if you are not smooth.
The RPM sticking or taking a long time to come down is just you not being used to the Z's throttle. While you're getting on the clutch, you're not quite off the throttle. The Z has a very sensitive throttle pedal.
Practice a bit more and try a couple things. Once you get the feel, you will know it.

 

It should be alright. You're prolly just not used to the way the Z feels yet, it'll come.

 

well it's been two months with Z OTL;;;;;

It gets so much tension to drive smoothly, if someone sit next to me. lol

 

haha I gotcha

 

The Z has a heavier flywheel?

 

haha +1

 

+1 on making sure you let off the gas completely. And again the Z's clutch is also touchy. Lastly, going from 1rst to 3rd, there will be a lag since you will be going from high RPMs to much lower RPMs. Just give it a bit more time and concentraion and then once you are used to it you can relax and enjoy it a bit more.

 

You are probably noticing how slowly the RPM's drop when shifting a Z. Drivers coming from Corvette, Porsche, BMW, etc. have the same observation. My understanding is that the slow RPM drop in a Z is a concession Nissan (and Infiniti for that matter) makes to meet USA emission standards. Anyway, it is very annoying.

-- Spike