WOW, that was one hell of a buy!!! I have staintune mufflers with cat bypass. The slip joints on mine were nice and snug and required no seal or sealant. I have no decel poping at all. I did install new triumph head pipe gaskets when I installed my custom header. I guess I could have reused the old ones but they look like copper and they crush when setting the torque on the nuts on the head pipe.