How "bullet proof" are our transmissions?

bcfromfl

The reason first-gear starts are so unpredictable and "wonky" (and probably the shuddering you describe) is because of the dual-mass flywheel. Nissan added the DMF to try to absorb some of the drivetrain noise/vibration, but in the process, contributed to the poor clutch performance. Other elements that make for poor shifting are the plastic parts in the CMC and CSC, as well as the rubber hydraulic lines.

Some Z owners are fine with the OEM clutch...I'm a bit more picky, I guess. I expect a predictable and consistent engagement point, and a nice feel of solid contact. I just upgraded to a ZSpeed clutch with the external CSC at 3,500 miles on my car, and love it. (At the same time, I upgraded the CMC to the HD RJM unit.) The new 20-lb. flywheel also revs more quickly, and allows for a nice growl between shifts as the engine can spin down a little more easily. The OEM DMF is about 33 pounds, I think.

You may consider skipping gears when you shift, if you're concerned about wear and tear on the transmission. Third is basically useless, and only really useful when downshifting into a corner. (If you're accelerating hard, and do a 2-3 shift, IMO, you're out of the power band much too quickly in third.) Normal driving, I usually shift 1-2-4-6. Fifth only gets used when driving in a 30-35mph zone. As long as you are matching RPMs, the fewer times you shift, the less strain on the clutch and tranny.