i actually just did mine about an hour ago, i'm replacing my clutch and needed to take my downpipe off and disconnect it from the cat. unless you don't intend on taking out your radiator and fans behind it, this won't help. if you already took them out then just spray on some WD-40, leave it for like a half hour, take a 13mm, i believe, wrench or socket and a rubber mallet. i swung the mallet from the driver side towards the passenger side. werked great and with ease, alot better than me using the socket with an ext. from underneath the car. i hope this helps, if you need any more info on how i took out those bolts, just email me at [email protected], good luck
do u have it off completely or is the cat still bolted to the down[i[e, if its on still takoe the cat of use a heat gun spray liguid wrench let it soak then have someone stand on the midpipe so u can get leverage and it should come righ toff.
just put a little muscle behind it. mine were very rusted. all i do is put the closed end of the wrench on the bolt and then get another wrench and put the closed end of it on the open end of the other end of the wrench. lock it in and push like i mofo. this works for me everytime it just takes some muscle and a minute at the most.