IF I recall correctly (see what I did there? no acronym)... Ally fly's aren't really worth it until you're pushing 800+ rwhp... even on street/strip cars. Maybe roadcourse trailer queens, but pretty sure the consensus was they are too light for mixed duty and midrange rwhp.
IMO go billet, lighter than the hunk of iron or whatever the stocker is... but heavy enough to not be a pain in the ass. I think for the 1/4 the ally flys were losing time over stock and billet ones up to a certain rwhp?
Shoot me if I'm wrong, I'll just duck.