I took apart my exhaust and intake components for WOT to port. Received them back. Proceeded to put everything back together. Then I run into this gasket which was thrown in a box with all my other gaskets. I have no clue where it goes. It resembles the aftermarket gasket in material and looks that came with the o2 housing, but obviously it is a different shape. It must go in the exhaust somewhere. Or possibly WOT threw it in the box when I handed him all the parts and it really doesn't belong to me. Anybody have any clues?

looks like the stock mid-pipe to muffler gasket.

it didnt come from me, unless it was stuck in a box.

Of all people to respond! I'll have to double-check, but you could be right! I was just worried that it was a gasket that was placed somewhere in the manifold assembly.