Ford: Cat. Converter on 4 cyl Contour (Mystique)

I want to replace the cat converter on my 2.0, 4 cylinder 95 Mystique
with a universal after market, $60 versus Ford's $900 rip off.
Does it have to be mounted close to the manifold as in the original, or
can it be welded in downstream on the exhaust?
Is it possible to cut open the original cat., and simply replace the
ceramic core, and weld it shut?
Thanks

"Kevin Brown" <net> wrote in message
news:net... 

I replaced the converter on a 96 2 liter Contour. I got mine from DMI.
http://www.catalyticconverter.net/
I think I paid $250.00 for it. It's not a direct bolt on tho, as I had to
rebend the metal tube to the EGR.