Impressive!
Having a supply of free carbon fiber plates and maybe oddly shaped parts that could just fit somewhere is a real treasure.
Have you considered raising the tire pressure a bit? The first few PSI above OEM tire pressure have most effect on economy. The higher you go the lower rolling resistance will be, but the extra gains will quickly get very minimal. Still, an easy 5% gain.
It is standing fairly high, so lowering it or a front air dam would help. Also, extend the flaps (wheel air dams?) ahead of the front wheels a bit and fabricate them for the rears.
Finally, consider the
65+ mods and
100+ hypermiling tips. Tightening the nut that holds the steering wheel is my favorite ecomod.
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2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
lifetime FE over 0.2 Gmeter or 0.13 Mmile.
For confirmation go to people just like you.
For education go to people unlike yourself.