Have to disagree... You offset / replace some gasoline usage with electrical usage. x amount of power ( HP if you like ) is needed to move the vehicle. Shifting more to electrical and away from gasoline is a good thing. Especially if you can then get that electricity from a RE source. The first step of PHEV IMA improvement is just by the removal / reduction of the needed ICE alternator function... this reduces the amount of gasoline you use per mile just my having to spend less of it to power your electrical systems... which add up pretty quickly. The Second step is PHEV IMA systems allow for the assist without the MPG / ICE hit in order to recover the electrical energy. The Third is by using additional assist you keep the ICE / gasoline usage to a minimum... getting the system to give you additional assist have been worked out for the Insight-I... I haven't heard about any of the other IMA owners diving into that technical challenge yet. Have you seen the UK Insight with ~6kWh of Li batteries and a MIMA system to give extra assist when he wants it? There is also Mike D's I think ~3kWh Lead Acid system. And at least 3 or 4 people I have read about who have set up additional battery capacity... they have all seen MPG improvements. could it be better... of course there is always room for improvement... one of my favorites would be for a clutch to be added between the IMA and the ICE.