Headers

They don’t save temps- that’s BS. Heat is heat and you wrap them to cut back on heat.
Manifolds are fine - but not for controlled power. REAL headers are built specifically for the individual engine and car, weight etc. Boxed units are a balance of looks cool and function.

If you don’t coat them expect rust inside and out. If you get them coated- longevity goes up a few years possibly. BUT will not protect from speed bumps.

Both my old MoPars have Doug’s with ceramic coatings because I like to feel “special.” Nothing more.