power difference is quite noticeable in the upper rpms, especially if you have an air filter that breathes better than the stock box.

 

I notice a substantial difference when i put my "ebay headers" on. gaskets are junk as i have to replace the drivers side but that was my own fault. other than that i like them.

 

i have been looking into those headers also and have found only one difference.
the gibson headers use 409 stainless while the ebay brand uses 304 stainless.
i even found a link that describes the difference. http://www.revver.com/video/1964523/...ainless-steel/
this link pretty much says to use the cheap headers. lol

 

t304 stainless is the most common when it comes to exhaust from what I was reading before I bought mine. I figured they would be fine since they use the most common grade of stainless and they have been for years.