I heard the DC is a pretty good brand, but what about this?

http://cgi.ebay.com/ebaymotors/96-97...spagenameZWDVW

A DC-S 4-2-1 CERAMIC COATED HEADER for only $25. Is it crap?

 

DC-S, as in DC-Style. Its a knock-off brand header. As stated in the Header FAQ:

Q. $8 for a header on eBay?? What, is it made of plastic?
A. First off, eBay stores get their money from the shipping. The shipping will probably be like $40, which is totally unrealistic. So the total ends up being about $50 for a brand new header. With eBay, it’s always a risk. You USUALLY get what you pay for, although in come cases you might get lucky. The header might serve its purpose very well for a long time, or it could crack within a month. You will probably have fitment issues, either with the doughnut style gasket not lining up or o2 sensor’s not reaching (amongst other things), so it’s a risk.

 

^+1
The same goes for
Mu-Gen and Mugen
Which you might find on ebay
ebay is full of knockoff brands, so look out

 

A header should cost you at least $150 new (Megan Racing Header) and most of the decent headers out there are $250+

A header/exhaust manifold is an important part of your car. Would you buy brakes for $25?