we never have problems with helicoils in our aero engines, so i cant see why your having problems with them in a bike frame? you must of been fairly yanking on the helical insert tool to be able to snap it, either that or it was some real cheap crap, either way they shouldnt break that easily, if your an engineer then there should be no problem, if not helicoiling simply drill out the thread to 5mm, then tap m6, simple enough............... your attitude to frame replacement is a little childsish, it is not select bikes or a manufacturing fault, its simply yours for using either the wrong length bolts i.e. being too long......... or cross threading them.... i sugest just repairing the damn thing isntead of moaning on here............ you dont 'quit' just because you cant set your bike up correctly, ive seen lads force incorrect bolts into frames just so they can ride......... its no reason just to give up because of this ash