From Ameinfo.com,
All BMW Z4, 1 and 6 Series models as well as the MINI Cooper S and the new 3 Series sedan are already being fitted with Runflat tyres as standard.
The great benefit of these tyres is that in the event of a puncture, and the complete loss of air pressure within the tyre, it is possible to continue the journey at speeds of up to 80 km/h, without the immediate need for a wheel replacement. The tyres are also available as optional extras for the BMW 5 and 7 Series and the MINI and MINI Cooper.