I've been told many times that there is something that goes between the bottom of the manifold and the mid-pipe on the passenger side. Is this true? If so, what part is it? I've been told it was called a "exhaust manifold gasket," but the guy at the parts place told me that refers to the gasket between the engine and the manifold. I am going to be swapping the mid-pipe sometmie within the next few days and I've heard that I need to replace this part. Thanks!