I like the current theme, though the front bumper fit would bug me.
The paint problem sounds like an adhesion problem, between the paint & primer, or primer & metal.
The cure for that is almost always stripping to a good surface and going from there.
Pretty sure Passon still does the OD and also sells the parts if you have a local guy or do it yourself.
Headers or manifolds is personal and depends on the car's theme.