Today I swapped the speed sensors from both cars without any result. Still the high idle when hot and as long the car is rolling. When coming to a stop idle is back to normal after a few seconds. To be 100% sure it isn't the ECU I swapped them for the second time. Again no result. Asked M3W Service France for advice and they came up with the suggestion to swap the throttle bodies from both cars. Keep your fingers crossed that this will do the job. Will keep you updated.
