Looking to buy a set of TPM sensors but having trouble confidently knowing what to buy. All I know these are 433mhz sensors.

There's information out there that E70 TPMS were changed during the life cycle, but no information exactly when.

Do I purchase just the sensor or the stem and gaskets? Any preferred vendors?

Any help is appreciated.

Current set is 7 years old and throwing malfunction message occasionally - likely due to batteries.