Header upgrade

gumper said
Obviously it would be nice to have actual numbers on 1 5/8 vs 1 7/8 headers. 20 or more is enough for me to say it’s worth the money. Trying to squeeze out every tenth I can.

I'd say there isn't one number, too many factors to call it. He did tell me they made more power than TTI's 1 7/8" header too.