I have in my posession 2 aftermarket flywheels, one of which I will install on my car, the first is a Fidanza ~7.5lbs made of Aluminum, the second is a Spoon ~13lbs made of Chromoly. I am posting this to hear the advantages and disadvantages of each.

My thoughts are that the Spoon is preferable because it gives me some added power by being lighter than stock, but is probably stronger and less likely to grenade and will work better with the Spoon clutch and pressure plate that I am going to install. The Fidanza sounds cool because the motor will rev quicker, but it will rev DOWN quicker too and I think would be more prone to grenading. All of this is on a relatively stock ITR (JDM 4-1 header, test pipe, 4.785 FD), thanks for the input.