I'm going back some years to when i used to help spanner a rally car. We had dire warnings about touching the caliper bolts because they were done up in the factory to very specific torque values etc.
Mood: My Jota goes rumpety rump! & I have my wife exactly where she wants me!
Lane748 You will have no problems relating to the tensile streanth of A4 S/S screws for your calipers, I have done this change to all my bikes with no problems.