Turbosteve33

Hello everyone,

New here to the forums. Sorry to be posting about ANOTHER 350z drive train vibration issue, but Ive tried searching around and nobody seems to have the same issue as I do.
I have an 04 Enthusiast and installed a JWT lightweight flywheel and clutch masters stage 3 clutch. I understand you get chatter upon engagement sometimes and do hear some rattling at idle (just the throw out bearing). But my issue is that I have a weird vibration around 4k RPM and beyond. It becomes a loud humming noise within the cabin. Basically starts at 4k and goes until redline, but does get quieter closer to redline. I do have Z1 hardened motor mounts so I'm sure that doesnt help. But even if I am at a stop in neutral and rev the engine, the vibration is still there. Cruising around is just fine, basically anything under 4k rpm I don't hear/ feel anything.
Just wondering if anyone else has this issue or is the flywheel/ clutch may be unbalanced?
I previously had a mid weight flywheel on the car and the vibration was worse. Swapped in the JWT to see if that would fix it, which it did help, but the vibration is still there. Not too sure if it could be the clutch or this normal with light weights?

Any info would be greatly appreciated. Thanks!!