If you are still spinning the tires (like me) with a lw flywheel and low rpm launch then traction is obviously the bottleneck- so the amount of inertia required will be lower because you'll spin the tires with a heavier flywheel anyway, and once your launch is over-> a heavy flywheel will have a negative impact on your acceleration rate. If you're planning on making your Z a drag car with slicks and skinnies in the front then the stocker flywheel is definitely the answer. ALSO you might want to consider going automatic instead as it will keep the power down more efficiently and allow the turbos to stay in boost.
