The most restrictive part of the exhuast is the header/cat combo. So only like 3HP is made from upgrading from the flex-pipe back. Changing to a migh flow muffler and removing the resonator is a viable cheap option.
Frank McCoy aka Mod-deth aka Mid Life Crisis aka SVT Doood aka mcgainer is a SCAM ARTIST
Pre98 Zetec - Some Mods