Hi Jeff! Thanks for the promopt reply. No, I am not talking about PDC. You see, BWM used two different types of tire pressure monitoring systems the Tire Pressure Control (RDC) system, and the Tire Defect Indicator (RPA) system (formerly know as the “DWS” system). The RDC system uses pressure and temperature sensors installed in each wheel as part of the valve stem. The sensors transmit their individual tire data to antennas mounted in each wheel well that feed to the RDC controller. This system is technologically superior, because it can alert you to absolute pressure changes (like when all four wheels decrease pressure over time), it is more sensitive to slight changes, and it can react faster. The disadvantage to the RDC system is that it puts a few ounces of extra weight in each wheel, and the system is more expensive and labor-intensive to retrofit. The RPA system uses the speed pulses from the ABS controller to calculate their relative rolling diameters. The advantage of this system is that it is passive (does not add “stuff” to your wheels and lots of extra wiring) and less expensive and easier to retrofit. It’s down side is that it is not as sensitive to pressure changes.BMW introduced the RDC system in the E38, and they may have used it in the E65/E66. However, the RPA system is clearly BMW’s preference, because they switched to the RPA system for all other models. Most much prefer the RPA system too, since they do not want the weight and complexity of a sensor spinning mindlessly in each wheel. The RPA is better suited to a high performance vehicle, and I suspect that BMW has similar priorities, since they dropped their absolute pressure system for the ABS wheel speed version. According to the BMW WDS, the RDC system will detect about 5 PSI pressure change. The RPA system will detect pressure drops of about 30% (roughly 10 PSI, depending on tire pressure).
In my opinion, Jeff- RDC will be a tough MOD, as it entails rotational and temperature sensors in each wheel. The RPA however, is what I am referring to, as it will be much easier to connect the module to the sensors. I just wanted to know if anyone had done it, and how was it done? Aparently, the installation is very straightforward, almost as if BMW has intended for us to retrofit a system like this. Hence, I thought that if the mod is simple and cheap, then why not?!?! Anyways, thanks for replying, and hope to get more knowledge on this as well as other things.

Thanks!

Kris