The bolt's are 12.9 you do not want to drill those out. splitting the caliper can't be very hard to do. After that you can just take off the swivel with the rest of the caliper. Grind the heads off , take the caliper off and tap the thread loose , while you support the ears on the swivel
I use a set of Rocky Mountain parabolics. On the front i use a set of oil dampers, on the rear there are a set of gas dampers. The difference is really noticeable. The gas dampers make it a really smooth ride