It is super easy to have these studs pull right out of the head.
Most of the time it is because it is over tightened. Some times it is due to sloppy installation methods of new studs in an old head.
I use blue or green loctite on the studs into the head and anti-seize on the crush-nuts (make sure you use the proper washer to spread the mounting force correctly). I also use copper gasket spray on both sides of the head-to-manifold gasket as well as the manifold-to-turbo and O2 gaskets.
Get a good torque wrench to make sure you do not over-tighten those crush nuts. If I recall correctly, it only takes around 20 ft-lbs of force.
If you take your time and use the proper parts and supplies, it will last 100K, if not, you will have leaks very quickly.