It will not function s a cat at all. But if you don't have to worry about emissions controls, I would consider getting the Random Tech Y-pipe (it removes the pre-cats). You could then cut out the main cats and just put a pipe in their place. And you would have zero post ignition emissions controls. Your check engine light would probably come on as the two o2 sensors in the cat pipe would now have the same reading, this is telling the computer that the cats aren't working, or in your case, are missing.
Best option IMO, replace the Ypipe with a Random Tech pipe, replace main cats with Random tech cat pipe. This will probably be as free flowing as a piped exhaust, and your computer will be content. And you will still pas emissions controls, unless you live in California.
This will run you about $600, but you can do it in 2 $300 steps. As I recall, the Ypipe is about $300, and the Random Tech cat pipe is about $300. Much more expensive, but also a much better outcome. And unless I am mistaken, the RAndom tech parts come as bolt-on pipes, no cutting or welding. So not only are you removing the factory restrictive cats, you are also putting in larger, more free flowing pipes in thier place.
cheers,
.
