I saw headers on ebay going for like 40$ are they any good or should i get a brand named manifold ?

There are some noticeable differences, but unless you're building something crazy, there's no reason to spend a lot on a header. One downfall of the cheap headers is that they tend to have fitment issues and aren't very strong. As for power gains, you wont notice a lot just from a header. It all depends on what you plan to do with your car...

Great:
http://hondamarketplace.com/zerothread/2027262
http://hondamarketplace.com/zerothread?id=2052395

Good:
I honestly cannot think of other companies that make headers....i've been out of the NA business for over 2 years :p


Meh:
http://cgi.ebay.com/ebaymotors/94-01-Acura-Integra-GSR-4-1-Racing-Header-GSR-95-97-98_W0QQitemZ130172523204QQihZ003QQcategoryZ33631QQ ssPageNameZWDVWQQrdZ1QQcmdZViewItem
-According to CivicSpoon, Pacesetter sucks...i can't argue with that logic :p

IMO, Pacesetter are garbage. My friend had a pacesetter header for 6 months and it started rusting (though, driving it through winter on salted roads).

^^I couldnt remember if they were good or bad....like i said, i've been out of the NA game for quite some time. What are some other mediocre brands??

Im swearing to megan racing headers from now on. From my experience they are great quality and a good bit cheaper than other brands. I picked mine up for my 02 si for about $120 when the dc headers were about $300. Unlike picking up something from ebay they fit perfectly and came with all the parts you need.

^^ Similarly, i'm swearing to not have another NA Honda...:p