Folks have varying opinions on what the best flywheel is.

The weight range for aftermarket flywheels is about from 8 to 12 lbs. I think the stock flywheel is something like 17 lbs while the ITR flywheel is 14 lbs but I'm not positive on those numbers.

There are also two methods of building them: either a forged one-piece chromoly steel unit or an aluminum unit with a replaceable friction surface (a clutch can't grab on to an aluminum flywheel). The difference here is that the aluminum units tend to be a bit lighter, and to service them all you do is replace the friction surface. The chromoly steel ones are a generally bit heavier, they have to be resurfaced or replaced for service, and they have a higher heat capacity.

Which one you choose is pretty much personal preference; they're for the most part all good. Personally I'd be inclined towards a chromoly steel one with a weight somewhere just a hair under 10 lbs. The two flywheels I know of which fit the bill are Exedy and Kaiten Karui (not Super Karui--it's lighter).

The one thing which would push me towards a lower weight is if I was running some kind of big brake kit with rotors that are heavier than stock. That's more weight for the engine to spin up so I would use a flywheel more around 8 lbs to compensate.