Why do you think you are going to have to drill them out? They shouldn't be on there all that tight, I think mine were rated at 25lbs of torque- not all that much. They should come out and go back in really easy, just make sure you're using a ratchet and not some shitty set of pliers that will strip them.
What happened with mine was that the guy at Advanced sold me the wrong pads and I didn't know it so my caliper wasn't fitting correctly over the new pads after i put the new pads on - the calipers wouldn't go back in line with the caliper mount. I went to tighten the caliper mounting bolts and they wouldn't move so I thought there was something wrong, I put some of my strength behind it (i have a ton) and it snapped one of the bolts in half.
I tried for a while but couldn't get that bolt out of the pin (see below)
The bolt on the right broke off in the pin on the left. I didn't think the pin would come out of the caliper mount so I thought i was fracked but it pops right out so I just went down to O Reilly and bought a new pin and bolt for $4.