You cannot install flywheel improperly?
There is only one way to install flywheel, otherway you car will not start?

 

The advantage that nobody has talked about in the JWT, is that when and if it ever needs a resurface, you just replace the friction surface, no need to machine it.

 

I would think that a heavy single mass flywheel would be a recipe for breaking something. The reason heavy flywheels are dual mass is to avoid shock to the drivetrain. Drop the clutch on a heavy solid flywheel, say goodbye to gears. I could be wrong, but I don't think a sprung clutch disk would absorb that much, that's why they're paired with a lightweight flywheel.

Unsprung clutch disks are paired with the OEM dual-mass.

Here's an animation about what's going on inside a dual-mass flywheel:

 

Correct me if I'm wrong, but isn't that why they have harmonic balancers? I mean plenty of cars use single mass flywheels and none are lightweight. I found this info just now....
http://www.directclutch.com.au/flywh...onversion.html