Among the many new devices promising to boost fuel economy during these times of high gas prices, the PLX Kiwi tries to improve the driver rather than the car. The PLX Kiwi is a training device that monitors driving habits and assigns the driver a rating based on how "green" it finds the driving style, with 100 being the best. For the most part, the Kiwi does just that, but issues with the way the device interfaces with the vehicle may leave some drivers scratching their heads.