It is a tough job. If you drill a 3/4 hole in the plastic fender liner, or trim the plastic away, where the front side sill mounting bolt is then you can have the side sills off and on in under an hour. It is your choice. Otherwise you will need to remove part of the front inner fender to get at this bolt. Remove your muffler clamp and remove the front cat mounting bolt and rubber hanger completely. Be sure to completely remove the T bolt and nut form each mounting ring on the cat to exhaust manifold connection clamp. Then if you use a long pointed bar and a hammer you can tap around the joint to break the clamp loose. Then expand it with your hands just enough to slide it up towards the engine and remove the stock cats. You do not want to get the clamps out of round or you will have a hard time reconnecting them. I shimmed up the cats with blocks and a small hydraulic jack so as to hold them in the proper position when installing them in the car and putting the clamps back on. Make sure you have the cat flush to the exhaust manifold flange and lined up all around before reinstalling the clamp. It helps if you reinstall the clamps with the nuts facing downward so you can get a socket on to them. Button everything back up and enjoy the ride. We do them here in our shop in about 3 hours but you had better expect to spend an afternoon if using jack stands and laying on your back with a creeper.
Robbie
