I have not done this on a porsche yet so I won't be much help but more than none. I think every pedal Ive had to do, the rubber does pop off. Some times prying with all your might and just about ripping your finger nails off. I like to find a wood backer for the pedals so when you drill the pedal doesn't move down more and you don't slip the bit. tape the pedal where you want it and push down to make sure it doesn't come in contact with the flooring etc. Use a scratch-all or center punch to mark drilling locations. Drill one hole then install and drill other holes with pedal in place. don't slip and scratch the pedals! then insert screws make sure they are short! 1/4" usually does the trick. You can leave the rubber on if you want. I like to take it off so if you sell you can remove the pedals and the rubber goes right back on.
