I have always found if there was enough force to break the stud or bolt in the first place then any of these easyout , or stud extractors are not much help,and often break themselves causing more prblems, i have come to learn that it takes a good few heat cycles combined with penertrating oil, impact plus the need to take time is the answer, when a bolt or stud snaps off i will weld something to the broken bolt top and with the above methods it will usually come out, if it don't then drill it out and fit a thread insert of some type
Pete