I attempted this the other week, and after removing one stud succesfully with the easy out kit, the easy out drill bit snapped off inside the stud. Was quoted $300+ to remove it because of the special drill bits needed.
Ended up removing the head as i had a spare head, but in hindsight the $120 it would have cost to get them out by a pro in the first place would have been money well spent.
Goodluck to you