DemonSVT
CEG'er
IIRC the Spec flywheel is just a fidanza remachined through Spec. My girlfriend bought me a Spec flywheel as a graduation gift, and when it arrived it said fidanza. I don't really care which it is, because it weighed 11 lbs. on the scale.
Then it was a Fidanza. A "true" SPEC flywheel weight is a hair under 9lbs. (also says SPEC on on it)
Both use the same billet blank. Nothing else is the same about them because SPEC builds the rest in house. Just like they do their clutches and pressure plates.