I wouldn't even try taking the pipe off of the cat if I were you, those bolts are beyond me. What you should do is just dismount your exhaust where the cat meets the header, its ot hard at all, and where it meets the muffler, you can even leave the muffler on. To tell you the truth, both me and my friend did short shifter installs without removing the exhaust, you just have to rip apart that heat shield that blocks the shift lever.