The lightweight flywheel, many overlook this upgrade because it’s not easy to do and can also be expensive. I was lucky to buy the car with this upgrade, and what I immediately noticed is that it revs much faster. Not only when you open the throttle, but also on the way down when you let it go!
As for drivability, I didn’t notice that much of a difference comfort wise. Yes, it stalls a bit faster but if you know your way around the clutch it’s can be managed.
I truely think this is an awesome upgrade if you have the knowledge and/or money. The mivec engine is meant to rev fast and not to be stopped by heavy gearbox equipment.