I just bought a 2018 911 GTS. I stored the OEM wheels and tires and installed a set of Avante Guard wheels that I had on the 2012 Turbo that i sold. The TPMS monitors did not work. My local tire store ordered and installed a set of monitors. 3 hours of waiting and $430. They never registered. The Auto Gallery Porsche wanted $1200 to do the work. My LA Porsche shop Monoco Motors and Tire Rack came to the rescue. They installed these and they fired up within 1/4 mile.

Size & Description Qty Availability Price Each Item Total
433MHZ TIRE PRESSURE SENSOR
4 In Stock $57.00 $228.00

I hope this info helps someone.