catalytic converter question

[josh_trdsparks]

I can't see how taking one working cat off and putting another one is going to help the car in any way, shape, form. or idea. To pe perfectly honest there really isn't any such thing as a "High Flow Cat" anymore. The new cats are (I believe) a 3 screen design and replaced the old "bean" stlye cats from way backin the day. They flow better becuase they are bigger hence the name High Flow Cat. They are more efficient and better for emissions as well. Since all new cars come with these style cats there isn't really a point in changing the one you have.

Yes there are a few cars that may benefit for these aftermarket cats like an Si civic or even the Celica GTS. But these engines don't work off of back pressure they like or need to be as open as possible because of the V-tec and VVTI-L. These cars also make most of thier power at high RPM's. The yaris doesn't work in the same way but we all know that. If you open up the exhaust too much you will actually lose HP. I wouldn't out anything over 2.25 in on it personally and that's pushing it to me.