I disagree, drive your car to a competent exauhst shop and they can fab you one for less than you think. Shop around though. Read the sticky at the top of the Zetec performance forum and you will see many good options.
If you have a pipe bender and good welding skills you could fab your own but...
The used SVT exuahst is good if you can get it for free or real cheap but I still don't think it's best for the 4cyl.
