Wrapping the exhaust components is the absolute best way to kill them. Holds the heat in, but doesn't keep any of it out of the part like coating the inside would. Death to components comes from wrapping them.
Stock up-pipes are worthless. The collector and dounuts and pipe bs is hopeless. No provision to accomodate the unavoidable expansion/contraction.
I've killed three sets of them all new each time, including the pipes themselves, as if that really matters.
My guy in Ga charges me $18 per linear foot to coat the inside and outside of anything with the black 2000* stuff.
I would never in 2 million years even consider ever putting the stock up-pipe crap back on any engine it ever came off of. A set of DI uppies would go back on or I'd make some myself.
Almost every stock truck we have has some varying amount of exhaust leak at the collector/dounut region. They are STOCK. And yet I drive around at 1800degrees WOT with probably 2 or 3 times the drive pressure and......nothing, no leaks in the uppies. No leaks at all.
Now the manifolds are a different story... workin on that right now