When I had a Sierra hatchback GT this had the same engine in as yours. I fitted a induction kit and removed the cat. The car was defo quicker with the cat removed. At the time a friend of mine worked for an exhaust place so he removed the cat and made me a pipe to fit where the cat was.

You could always fit a mk5 escort RS2000 engine. I've heard of people using the 2.3 engine out if the Ford Galaxy.