when i first got my 1980 w123 230 sedan - i was doing basic maintance and broke off one caliper bolt in the front. (i did not mean to, it happened)

yes i drilled it out. - it was too rusted in from no locktite or neverseize being used - could not use a bolt out bit (a reverse cut drill bit) or other basic trick.

found center, center punched, pilot drill, and worked up to size, rethreaded and cut out the old thread as tapped new threads at the same time all together...

people beleive in helix coils and such - each to their own.
Jake