come off. Break the bolts at the junction between the pipes from the cat and the pipes to the muffler. Then just unbolt the muffler and let it drop. get something to rest the new muffler on the will hold it kind of to the height it will hang, thread the bolts at the junction. The only hard part is getting the muffler brackets back on, I laid on my back with the muffler on my belly with the brackets lossely around it, used a pair of vice grips to get the bracket closed enough to thread the nut. now just tighten all of your bolts and you are done.
Those who doubt me suck c0ck by choice~Tom Nutall.