Weight reduction and engine downsizing are both expected to play a major part in achieving great efficiency in the Z10. Aluminum and carbon fiber are expected to be used in new ways to keep the weight to just over 3,000 lbs. In typical BMW fashion, power may come from a new inline six cylinder using direct injection and high pressure turbocharging. The engine may also use electronic valve control for variable compression ratios. Mileage should get a further boost by adding automatic start stop to its new seven speed dual clutch transmission. Finally, an updated version of the brake energy regeneration system that BMW uses on many of its current European models will get a lithium ion battery to make it sort of a pseudo-mild-hybrid.