header vs. header?

I was looking at headers on ebay and was wondering what the real diffs were between the dc headers and the headers that are like 200$ cheaper (79.99+s&h). They weren't name brand but looked exactly the same and had same tubing, help me out plss....

Not sure but they may be less able to hold heat and will radiate heat into you engine bay... and they may not have the O2 sensor hole and thread so that your engine can get readings...

Typically (not always, but generally) the ebay downpipes are made with cheaper metals and welds and have tendencies to crack at the welds (especially if they lack flex sections). As well I have heard of alignment and fitment issues that have arisen with ebay downpipes. Now obviously, all the same issues have occured with name brand headers, but not nearly as frequently. Ebay is always a gamble...