drill and get the ez-out kit, alternate hot then cold and tap tap tap on the ezout once installed. If this does not work, then you would be looking at a heli coil after you have drilled out the bolt. In anticipation of possibly having to do the heli coil, make sure the ez-out hole is dead center of the bolt.

Also soak it for 24 hours with PB-Blast about the best penetrating oil around.

__________________
John
2001 ML 320
1988 560 SL
2009 Toyota Tundra TRD
1992 400 E (sold '07) (bought back, '13)
2008 ML 350