I just bought a 2 piece Airmass header (4-2-1), and I finally had a really good look at it. Besides the missing O-ring gasket, and the instruction sheet's advice to "re-use the old manifold gasket", the overall workmanship is pretty, well, crappy. When looking into the bottom end of the main header, you can see that there is much overlap where the two downpipes meet the flange (see image #2). Also, the main flange has lots of rounding in the main port area (engine side, see image #3). What's thedeal here? You guys have bought and used lots more of these things than I have; is this typical for a header, or is this low-quality? Also, for my second question, it would seem that a one-piece header would be lighter and have better flow qualities than a two-piece. Having said that, are they a lot more difficult to install? After looking at this Airmass piece, I am very tempted to get a DC 4-2-1 one-piece header! Any advice most appreciated greg v ('91 Civic Si)

P.S. sorry, I thought I could attach an image to this post. e-mail me if you want to see a pic of what I'm talking about tx gv

 

Airmass isnt exactly top of the line.
If you go for a 1 piece header, you will most likely have to remove the front crossmember to install it. But, who cares. thats only gonna tack on another 15 mins to the install time.