MultiAir brings hydraulic control of valve timing to improve internal combustion engine efficiency. Improved power and torque enables smaller engines, less weight, which leads to improved economy. Interesting that an improvement in fun is also claimed thanks to more responsive engines. This is "hybrid killing technology"?
"Hybrids should only be used if there is no other, cheaper, way of making a petrol engine more efficient. Unfortunately for Toyota there is" - Rinaldo Rinolfi, VP Fiat Powertrain Technologies (See this post)
See more at the Fiat MultiAir Technology Home page