Hi,
They actually look pretty good, simple, fairly accurate technology. A couple of concerns:
- 1.) The battery is self-contained and not replaceable, so every other year you need to buy a new set.
2.) This device is self-calibrating, but only once. So, you need to make sure that your tires are at the absolutely correct pressure (cold) before installing the cap. If it isn't, you don't get a 2nd chance and so the cap must be replaced.
3.) The Boxster is pretty sensitive to wheel/tire/pressure balance. This device states that it has a 4PSI sensitivity (not the world's best). This 4lbs. could have an effect on the way the car feels and/or drives. It would also be a good idea to have the wheels balanced with this device installed to minimize any risk of annoying vibration.
Happy Motoring!... Jim'99