I've removed and installed several pairs of mufflers and have never used any sealant. Never had a leak but if it does make removing the mufflers easier I would say its a good idea. They can be a little stubborn to remove!
If the stock clamps are good you shouldn't have any leaks. I don't use sealant but I smear some anti-seize in side the muffler. Sure makes them come off and on easier.
If you use new clamps, probably not necessary. But I use copper hi-temp silicone at the joints, just to be on the safe side.
Originally Posted by SmokeyJoe101
Ditto
Originally Posted by zeke383
Me too...and contrary to popular belief, I find them easier to remove with a thin layer of the copper goo
Originally Posted by kink04fxd
If the stock clamps are good you shouldn't have any leaks. I don't use sealant but I smear some anti-seize in side the muffler. Sure makes them come off and on easier.