I think the flywheel you talking about for sale is mine. I actually had a streetlite flywheel with the Spec when I bought the car. It was a great set up, and actually I wish I would have stuck with it. There was almost no chatter, and it held a lot of power.
When my motor blew I went with a Southbend clutch because I get wholesale cost on them, and I got another streetlite flywheel (the one for sale) and it was also a nice set up. No chatter at idle, a slight chatter when I was learning how to drive it, but after I adjusted I could drive it like any other clutch.
I made too much power and the clutch started slipping, I had to send it back to Southbend and they upgraded/rebuild my clutch. They informed me that with the new clutch I got the light weight flywheel was not recommended and the clutch would not be warranted if I dident use a OEM one.
Looking back, I love my south bend clutches, but I think the Spec with the streetlite was my favorite set up I have had so far.