I was told that the reason the BMW stability/traction control system could not be used is that the software would need re-writing to work with such a light car.
So significant cost.
Same with the AEROs, the TC stuff was developed for a car that is 500kg+ more than an AERO.


Peter,
66, 2016 Porsche Boxster S
No longer driving Tarka, the 2014 Plus 8...