A couple of points regarding increased combustion pressure and bearing loads.
If I have got this wrong its because of a failing memory, what I recall is from lots of reading and research 20+ years ago and I dont have the time to re-read the books even if I could remember where they are
Anyway I am sure that I can recall of reading about common forced induction myths including perhaps the two above.
I am pretty sure that for the same RPM the bearing loading was actually less on a forced induction car as the pressure on the piston (I have forgotten the term, something like BMEP) was more constant, or perhaaps that should read less pressure reversals, it was all to do with the induction stroke that would normally have a negative pressure and with forced induction positive.
Regarding the combustion pressure and head gasket loading, well the compression ration is correspondingly reduced to end up with IIRC a similar combustion pressure or detonation would destroy the engine unless special fuels were used.
Forced induction is all about increased volumetric efficiency (breathing) higher torque at any given speed without the need to rev the engine higher which is what usually causes tuned engines to let go, On the other hand higher voluletric efficiency means more fuel air mixture and greater power so I can see that logically there must be more combustion pressure being resisted by the head gasket.
I would love to hear your comments which may help blow away the cobwebs clouding my brain, I think the what I read and think that I recall may have been written by David Vizard.