может уже обсуждалось...на 11 прототипов 8 серии ставили датчик давления в шинах !
Tyre Pressure Control (RDC)
The 8-series was meant to be the pinnacle of technical possibilities for BMW in the early 90´s. Numerous hitherto unknown technical features supposedly ought to have been in the E31´s cradle, amongst them a system called Tyre Pressure Control (abbreviated RDC in German).
Tyre Pressure Control was installed in 11 E31 prototypes before the decision must have been made that the system was not yet ready for public consumption. The button depicted above can be seen in the BMW convertible prototype which is currently on display in the Munich BMW World Museum.