If PP does not have it, here you have a OEM factory part:
Throttle Body Switch Micro Switch 100 Genuine Porsche for A 911 Carrera 84 89 | eBay
This is the cost of this switch $200 crazy expensive for what it is. I've never seen anything but the factory part available. They run about $200 all the time.
While at it remove the WOT switch, most are easy to open up. Open it up and clean the contacts with 600 grit sand paper. If it's the newer sealed unit I suggest testing it as well to be sure it closes (reads 0 ohms) at about 80% throttle, once it closes it needs to stay closed all the way to 100% throttle.
Also be aware that the idle switch has a very specific procedure for how to adjust it. You DO NOT ever want the idle stop to become the switch! The idle stop must be the stop screw and the linkage must NEVER hammer on the switch. At idle stop you move the switch just enough so it activates (red button plunger) clicks on. You do not want excessive pressure against the switch as it will damage it, very likely what damaged that switch you have now. I usually remove the TB entirely from the car to properly set the stop screw and the switches, I also look very carefully at the throttle plate to be sure it's not hitting or rubbing inside the throttle body. Basically a good time to look over the entire throttle body.