Originally Posted by ripto
Ok, I guess I just don't have a clear picture of what the stock exhaust system looks like, and I can't seem to get a hold of one. I notice cat-back systems go from what looks like a resonator to the tail pipe, I'm not really sure what's ahead of that, but from what you're saying, it must just be the manifold/cat, some pipe, and then whats included in a cat-back system.
From the bottom this parts diagram from Fordparts.com shows the exhaust routing from the engine back to the rear muffler (shown top right).
From the exhaust manifold lies the first catalyst, if equipped the secondary catalyst is located immediately behind this first one. (PZEV and California spec Emissions vehicles only afaik). Then comes the first resonator/ muffler, then more piping, a secondary small muffler, and then the lunchbox out the back.