The dude doesn't give a brand name to the headers, which should be your first warning sign.
Also, I've never heard of "polished ceramic"...is that legit? I honestly don't know
Thought it was either ceramic or stainless steel, and those look like stainless steel.
"Race" headers usually involve eliminating the cataylic converter. The header in that picture is not long enough to do so. I really doubt you'll be seeing a 8-15 hp gain from a set of 4-1 shorty headers.
Those would be my major concerns if I was considering buying those headers.