what does head studs, and frame mount studs have to do with his exhaust stud breaking off?
sounds to me like he just overtighened the exhaust mounting nuts.
That's one thing i notice a lot...people over tighten things, which usually ends up breaking the stud. another thing is that a lot of people are limited on tools and they may use the wrong tool for the job i.e. an adjustable wrench, channel locks, vise grips or pliers.
I know that a lot of people here are not mechanics and they do not have access to a full tool box of tools, and they use whatever they have on hand to do the job.
on the exhaust, the nuts do not have to be more than snug...they use lock washers for a reason, and they do their job. once the gasket gets hot, it will swell, and actually make the nuts tighter just by it swelling up.
just like an oil filter on a car, there is no reason to ever use a filter wrench to tighten an oil filter. hand tight will be fine because the rubber gasket will swell once it's hot and it will make the filter tighter.
I don't mean to sound negative (if i do...i'm sorry for that) but i just wanted to point out some things that i "see" happening.
even tho the china motors do come with cheap, soft studs, they won't break if you don't overtighten them.