i haven't had time to read all this, but the short answer seems to be lack of tune and inadequate waste gates to keep the turbos in check.

compressor maps are fairly easy to read, garret even has a tutorial in reading them.

seems that the lack of tune blows up rings, there may be better rings out there, but that's no fix, getting a good sleeve put in and getting the block o ringed would help, but you still need to lower the static compression if you want to run 15 psi on pump gas!

a knock sensor would be part of a engine management system, but if someone wants to make one that will dump the vacuum advance ( maybe even retard the mech advance???? ) as knock gets louder, that should be fairly easy.

maybe get a motor that's reliable for 50,000 miles at 5 psi then crank up the boost as you can get it running properly.

it's easier to run high boost with MPFI... carbs are going to have issues that kill motors. ( yes even well tuned ones some times have problems that mpfi can never have and kill your motor. )