Here's a cheap jack pad that works specifically for a Porsche 718. Take a good old hockey puck, drill a 1" dia. hole and insert a 1.5" long 3/4" (1"OD) PVC pipe.
The PVC pipe inserts into the jack point hole and holds the puck in place so it won't shift while jacking. I made up 4 of them for my Quickjack.