I just wanted to throw this out there. Just to help anyone who needs it. I tried to take my rear firewall cat out and the bolts were messed up. I eventually got it and the manifold off in one piece through the firewall and motor. I got a new manifold and bolts and put the new cat in. My SES light didnt go off. I drove 75 miles one day and worked for eight hours. I started it up to go home and it didnt come back on. I needed to drive it aways to get it hot i guess. But all is well with it and thanks to the ngk's she really runs smooth. So if i can offer any advice to someone wanting to try it yourself just ask. Thanks for having me and have a great day.