First thing to do before installing new o-rings is to use a piece of Scotchbrite pad to take all of the gunk out of the pipe inside, and be certain that the surface is really free from any nicks or deep scratches. Same for the exhaust manifold, in particular the grooves. They should be CLEAN.
For years, I only used a bit of clear silicone lubricant that came from NAPA on the o-rings and inside the pipe. But I have found that they last longer if I use some of the silicone sealant that Sanford refers to.
I’d be curious how well the pipe and manifold fit. They should be tight and not easy to bring together when the rings are on the manifold. The one other thing not yet mentioned is the springs used. If they are not strong enough, too much chafing will result, and premature failure of the o-rings will result.