interesting read, but not really what he was asking. He wants to know, rather then change over the cat-back 1ZZ exhaust for the 2ZZ exhaust as many people have done with great success, is it possible to change the cat too (this would save time and effort and if it fits on the 1ZZ headers, you could do the change over yourself at home pretty easilly) does anyone know if this would work or is Tom the test case?