OK for my sanity, will everyone please STOP saying HEADERS while speaking of there 4 CYLINDER CIVIC!!! You have a HEADER, note the absence of the S, that is because YOU ONLY HAVE ONE! UG biggest pet peeve exspecialy when the same thing is done over and over again. /end rant

Now it relation to your question, it is VERY simple job to do even with basic handtools. I would say that if you want to get something from ebay, get atleast a DC sport manifold, and make sure its either stainless (make sure its 321 stainless as you may see some 304 and 409, and those tend to crack at high exhaust temps) or ceramic coated. This will keep it from rusting and looking fairly sharp over time.