I just replaced my brake pads on all four corners with Cool Carbon. Here are some tips I learned in the process:
1) You don't have to open the brake cylinder cap for a even pad swap. If you are swapping out run out pads with new, then yes open and take out some fluid if necessary so you don't over flow when the pistons are pushed in.
2) You don't need to take out the 4 torx screws on the caliper. Like some one mentioned you can easily angle in the new pad on the spring clip and insert the pad into the recessed area of the caliper.
3) I believe it's certainly acceptable to remove the two hex caliper bolts for pad replacements. My Porsche uses the same basic caliper and the bolts are the same. I checked the Porsche Bentley manual and the torque specs are 85 n-m or 63 ft-lb. No problem here for caliper removal and it's the method for the Porsche when you need to replace the brake rotors.
4) A simple method for pushing the pistons in is to use channel lock plyers with some duct tape over the jaws so you don't scratch any paint. Squeeze the brake pad tabs with the four torx screws to pull in the pistons while the pads are still installed. I used this method all the time on Porsche Brembo calipers, but it was pad tabs to actual outside caliper. Works great. The rears can be done similarly with the big metal weights if necessary. But as indicated here you can use your fingers/hands.
I think that was it. A very simple process, but I prefer the Porsche brakes overall. They are simpler and very quick to swap out pads. You don't have to remove the front caliper on the Porsche either. Only one pin per caliper to remove.