So i went through this on a customers car last november.

His DMF was destroyed beyond repair

We ended up installing the Spec Steel single mass flywheel
The specs are wrong

we weighed them

stock flywheel was like 31.6lbs say
the spec was 28.7? if i recall correctly pretty damn close,

He does not run the RS barn dampner and has no issues so far, multiple track events and is smooth.

 

the DMF or crank damper isn't so much for NVH as it is for engine durability, though it does help NVH to an extent.

the crankshaft twists along its length and flexes with power strokes which can beat up the main bearings and break the crank in extreme cases.

the DMF or alternate crank damper greatly reduce the effect of that flexing/twisting and prolong crank and bearing life.

 

The 968 Turbo S and RS had solid flywheels and used the S2 vibration damper with it. So to minimize crank vibration a stock S2 damper or similar is a good idea as previously mentioned.