One of the best tricks that I learned in my years of wrenching in the rust belt is this - I have used all types and styles of easy outs including Snap-on, MAC, Cornwell, etc . All are pretty expensive and not covered for breakage either. Center punch the broken stud as close as possible to center ( I really like the automatic ones ) use a 1/8 drill bit( you can pick up the high speed double ended ones at the parts store for not much money) drill all of the way through the broken bolt ,soak it with PB blaster, tap in a quality t-15 Torx bit (like Snap-on)until it bottoms out, then use a 1/4 in socket and ratchet to rock it back and forth. Sometimes it has enough bite, but if it spins move up to a T-20. The best part is if the Torx bit breaks simply use a 1/8 punch to knock the broken piece out the other end so you can drill the broken bolt out if need be without the hardened broken bit causing issues. Best of all is the Torx bit is covered under warranty.
