It'll rev quicker with the flywheel but when you shift you might notice the rpm drop is more than it would be with the stock one. A heavier flywheel will hold the rpm better because it has more weight to keep it moving. The lighter flywheel will slow down faster but might be snappier.
As for the drive shaft I'm sure an aluminium one will be better than a stock one but I don't know how much better. I can see less rotating mass and quicker response but idk.
I don't know a super lot about the drivetrains but mainly people say the biggest difference is in vibration and noise on the highway and the overall weight difference from stock is only about 6-8lbs. Just doesn't sound like a mod that i would get excited for and could prob spend that $400 elsewhere and be happier Just my opinion.