2000 Ford Focus California catalytic converter

Depending on the State you reside, you should check with the Dept of Transportation. I know in my State, if the car is no longer registered in California, then only federal standards apply. This would include a Universal catalytic Converter in most cases. However, If the car is licensed in California even though you are no longer in their domain, the Ca. Emissions standards will apply. So, if that's the case, you are in a catch 22 if you need to pass an emissions test, unless you aquire a waiver from the DOT allowing federal standards replacement on a CA. Licensed vehicle, so that it can actually pass a test and be licensed in the new State. (I am only using my State requirements as this guideline). Also, if relocating outside of the USA, you may obtain a DOT waiver to have the emissions removed if you are going to use leaded fuel outside the country.
Good luck, Check it out with your DOT.
If federal compliance is the standard, you will save a ton of cash using the more inexpensive replacement converter. (Some still require duel in-line converters depending on the model and drivetrain, or a duel in whick is also expensive, but still about half of a dealer replacement.

I want to add, I hope the diagnosis is correct. Was a vacuum test or gas analysis performed? Does it smell sulfuric? Although cases such as yours do occur, (I've seen my share), it is less common than usual symptoms. .

Sorry I forgot to mention that I am now in utah. I dont believe the mechanic did either one of those test, he just plugged in his computer thing. I cant see any difference in my cars performance from now and before the engine light came on so I dont really care to get it fixed if I dont have to. The problem is just getting it good enough to pass emissions and I know that wont happen until that engine computer says ready for the catalytic converter. Two guys that I have talked to here say that unless I get the exact replacement converter then that engine light wont go off and I am screwed. I hope that they are wrong though.

It doesnt smell at all