You have to give it more than a couple hours for a response. Your original post was posted when most people are at work. As for your idea, the cats aren't really the problem. They flow enough that just replacing the y pipe is much easier and cheaper. Also, I believe some states are still strict when it comes to high flow cats being installed. The pricing for something like that would be expensive, not because of the y pipe but because high flow cats aren't cheap. That's why people go with just they y pipe cause it can be gotten for something like $20
Supercharged, cammed, other things too!