I have verified that he has the o-ring in there already. I believe the OP thinks that the OEM replacement style pipes would be a solid mount. The way the OEM replacement attaches is the way the OEM pipe attached. It uses an o-ring and clip like a lot of connections are these days on intake and radiator pipes. Anyone that has removed the factory plastic piece will know what I'm talking about. Anyone that hasn't removed their factory pipe, go out and wiggle it. You will notice that it moves freely because it doesn't use a form of solid mounting like a bolted connection. Thus the name OEM replacement. It attaches just like the OEM pipe does.