You can put a high flow cat on you would just have to move the flex pipe. My high flow cat is under the car (since I have the header) and my flex pipe was removed. I will be putting one on very soon. I don't like the rasp.
Hector
2003 Rally Red Mitsubishi Evolution VIII
257HP/259TQ
2005 Lapis Blue Mazda 6s
RET: 00 Cabernet Red Ford Contour Zetec ATX SUPERCHARGED
160HP/141TQ
