What About a Hybrid 911 Carrera?
 

Some will think this heresy, but I have been thinking that a hybrid gas-electric 911 would be very cool: lop off two cylinders and go with a gasoline engine of about 2.2 liters and 200 HP/170 ft lbs torque. Use the space freed up by the two cylinders to install a hybrid-synergy type electric motor/flywheel/tiptronic gearshift with about 50 HP and 250 flt lbs of torque and regenerative braking (that torque is do-able, too - electroc motors produce incredible torque). To save wieght, store the electric energy all or in part in supercapacitors instead of batteries.

The car would probably weigh about 80 lbs more than an all-gas model, have a top speed of about 145-150 mph (far below the present Carrera's, but that would be fine with me, I've never had mine over 125) but it would get 35-40 mpg in town, and jump off the line like a GT3, with 450 ft lbs of torque.

I doubt the cost of the hybrid would ever re-pay the gasoline savings (at least if gas is only $3 a gallon)but as an engineer, efficiency appeals grteatly to me, and the idea of nearly doubling in-town efficiency is intriguing, along with the 0-60 acceleration of around 3.5 seconds it would have.