Long story short, I purchased and installed Oro-Tek OBE-007 TPMS sensors on a second set of wheels, to use in the winter. Cross-referencing several manufacturer's literature gave me about a 50/50 likelihood that these would work correctly for my early VIN MS. I believe that these sensors will work on the Roadster and made the assumption that the early version MS's would use the same sensor. For the cost ($16 each), I figured it was worth giving it a shot. Ever since I mounted the wheels, I received TPMS system error. I'm not certain of the exact verbiage, but assumed that these were not the correct sensor and were not going to work at all. However, the other day I began receiving an additional error message alerting me of a "Low Tire Pressure", in addition to the other error message. This was very surprising to me, as I had assumed the sensors wouldn't be communicating at all. I checked my tire pressures and found one wheel to be about 37.5 PSI, so perhaps they are working despite the constant error message I'm receiving.