I'm debating on what flywheel to use with this engine i'm building. It'll be raced but nothing more serious than test and tune and romping on the back roads, so i don't know if an SFI approved flywheel is really necessary. I don't see it ever revving past 6500 RPM. I'd love to have an aluminum flywheel but i'm trying to stretch my funds as far as possible. So, my options are basically a billet steel flywheel off ebay for $120, or a cast iron stock replacement built by Zoom for $50 from the parts store. Is the $50 version really all that bad if i'm not going to be revving it to the moon or doing 6k clutch drops?