Saki GT

You are looking at more than a seven pound difference because you need to consider rotational inertia, and more 30% mass means exponentially more energy is stored in the flywheel at speed., especially as engine rpm increase. Spin that disk up to the engine's 8-9k rpm speed, and you have a lot of energy to deal with.

Also, to go to your original statement, the weight of the flywheel has nothing to do with clutch wear per se - that is more the job of the pressure plate and its ability to stop the clutch disk from grinding along and thus wearing out.

Take out the driver and driver behavior for now and focus on the system itself. The flywheel is essentially attached to the engine, so its mass effects how quickly the engine itself can spin up, and when you let off the gas, how quickly rpm decrease. It essentially stores a bit of energy as rotational inertia, and the more mass, the more energy it stores. I'm not getting into why you'd want that right now, but basically, more mass, more inertia, more stability.

Why did Honda put in a heavier flywheel? I think it may be to avoid mechanical overrevs, since it will act like a damper and now take a bit longer to spin the engine up to where it can be damaged, also, maybe to compensate for the shorter high-band VTEC range and to help conserve energy between shifts. Heavier flywheels also give the car a more poised temperament vs go-kart temperament. many S2000 owners have killed their engines by mechanical overrev and not reacting soon enough to stop it - a heavier flywheel slows the process down enough to give an attentive driver a chance to stop it before its too late.

Regardless the mass of the flywheel, it is the pressure plate that ensures a good connection between the flywheel and transmission by ensuring the friction disc - aka clutch - doesn't slide. When honda put in a heavier flywheel, it did not upgrade the pp to compensate, and that is why an AP2 will show rpm float at a redline shift but not at a 5k rpm shift - there is a point where the rotational inertia force overcomes the gripping force the OEM pp can apply.

The CDV on the S2000 is a damper that ensure strong, methodical action. It applies enough force to ensure a good, quick connection without introducing shock to the system. Think of a pneumatic door spring - the door will shut with authority but it will not slam shut. My best guess, since Honda has never stated such, is that it was introduced to protect the diff from shock, something that killed the diffs in many AP1s.

Saki GT

If you use an AP2 flywheel with improved pp and whatever clutch disk, the car will feel like it does now even though shifting action will be different. If you use an AP1 flywheel, the car will have a lighter feel since the rpm will change more rapidly.