Steve is correct. You need that rotating mass (steel) as opposed to steve does not, because he has that big leaf blower.
If ya got the money Billet steel no questions asked. There is nothing wrong with a stock replacement flywheel. It is what I will be using.
EDIT: I forgot you have a supercharger. I'd go with the billet steel. You aren't pushing serious numbers and it is a daily driver I take?
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"Gripping the wheel his knuckles went white with desire, the wheels of his mustang exploding on the highway like a slug from a .45. True death. 400 horsepower of maximum performance piercing the night, this is Black Sunshine"