So looks like this is something every 6.9 owner should do? Is it difficult? This article has convinced me my truck is awesome and I should spend more money
IMO, it's at or near the number one structural improvement you can make to a 6.9 or 7.3.
The job is not "easy-peasy" but it's straightforward. If your truck hasn't been apart for a while, or never has been apart, expect to find other issues to deal with, such as to the cylinder head. In most cases, you would undertake this at the time you pulled the heads for a valve job or were overhauling the engine. IMO, most often you can't do an adequate job installing a stud kit without pulling the heads, though some have done it. I'd only consider that road if I knew the head was fresh and the gasket was a modern one.
That pic is of my engine in the midst of an overhaul. Mine has been turbocharged since new and, to some degree, with the original head bolts and gaskets, a turbocharged 6.9L i a head-gasket-time-bomb. Mine blew a head gasket rather spectacularly so I decided to pull the engine and overhaul it. The lower end and cylinders were still in awesome shape but the heads needed a lot of work. I freshened everything up, added the studs and a modern gasket, updated to 7.3 rockers and she's been a good running farm truck these past nearly 10 years.
