Buzz,
I am no engineer and am not trying to BS anyone, just going on my own experience and that of my friends. I do know we drove each others cars quite often and I could tell the difference in how fast mine slowed down compared to his. Maybe it wasn't the flywheel, but except for that we had identical engines right down to the stroke and power. I know his did wind up a little faster but I didn't think it was enough to justify the extra expense for a street car. And I had no problems at all when racing in keeping up with or passing him. I could drive deeper into the corners as he started braking about a car length before I touched mine. Truthfully I had always thought that the steel would be slower to stop also. Maybe there was something else about his car that was causing this. We had the same compression, but I had to watch mine to keep from hopping the rear wheels while I could downshift his at the same RPM and it didn't do it. I am not trying to convince anyone that one or the other is better. I just answered the question from my own experience.
Ron