I'm looking at a set of 17in OEM alloys from a 2007 Ford Fusion for my 2008 Miata. They've come with the OEM TPMS sensors. VDO offers aftermarket TPMS sensors, and one in particular lists compatibility for both cars, the SE10001HP specifically.
Question: Does this mean I can use the OEM Ford sensors on the Miata? The Miata TPMS sensors will remain with their wheels, which will eventually carry snow tires.
I would think so. There's only a few TPMS manufacturers and Ford/Mazda has been a couple for a while now. While I worked at a Toyota dealer we had a vending machine with third-party small parts, including TPMS sensors (it's a thing). They were in there by mistake and I successfully got one to work on a Sienna, when I was supposed to get the Toyota part from the counter. Just takes a third-party programmer.
Moral of the story is call a local independent shop and have them give it a try.
As long as the frequencies are the same, I think you're cool. If you spec out wheels for each vehicle on Tire Rack, they'll tell you details on the sensors they'd install.