Plug-in electric vehicles might, one day, be a big hit but the Poulsen Hybrid kit will allow compact car owners a piece of the action early. The upgrade works by incorporating two electric motors on each of the drive shaft-equipped wheels in a moon rover-type fashion. (FWD or RWD compatible) These motors do not drive the wheels entirely but rather provides an extra gas saving boost while traveling between 15 and 60mph. The makers claim that a previously 30 mpg car transforms into a 50 mpgcar with the kit installed. Interested? The $4,550 kit gets you lead acid batteries or $8,600 for the lithium ion edition.