My 2020 2109S has the factory installed TST system. I'm quite pleased with it. This is the brand TPMS I decided I would buy after researching different models. It's basically the same as what you can buy aftermarket except that the factory unit has the tire sensors mounted inside the tire and held to the rim by a large circular clamp. TST says the battery life is 3-5 years. When the batteries die you'd have to have the tires unmounted, or at least have one bead broken down to replace the sensors. It would be cheaper at that point to install the valve stem sensors.