I am trying to squeeze every last ounce of power and economy out of my old 91. There are about three sets of factory headers at the local pick n pull. Will the existing exhaust pipe hook up to the headers, or are the different between headers and manifold?

This is a low budget, junkyard repair items car. If there are great aftermarket parts, that is cool, but I am really not interested due to cost.

 

ex and se match up
lx and dx match up

 

You could try to do some porting at the flanges as well. People have shown improvements by doing the same thing with RSX's(using an 05-06 type-s factory 'shorty header') and have shown gains similiar to a shorty style header for the cost of a little work and whatever they bought the factory manifold for.