Those of us who live in the real "great white north", or close to it, block our grills for 6 months. Doing so means I have no problem with mist on the inside of the windshield. When the outside temp starts getting up to +15 C (around 60F) I start to think it may be time to remove the blocking (pipe insulation fitted over the grill), but even at 20C ambient it doesn't cause any problems. The "Scangauge II" shows normal thermostat controlled coolant temp. The limiting case is, btw, on the highway, because the engine is at maximum power production, which means maximum waste heat. In the city the engine only runs part of the time, so will cool off between runs. As far as energy loss, it's not the air going -into- the engine compartment, it's the air going -through- the engine compartment, with drag around the bits inside. If it were an open ended pipe at the front and closed at the rear it would act as a solid aerodynamically. The shutters (or our grill blocking) do two things. Reduce the through-air drag, and help the engine to actually warm up, something it doesn't do in the city at -20C. I -suspect- the drag is minor. Warm-up is the big effect.
Lime green is also a handy color for Uber drivers. Sea Glass Pearl is not in 2016's color line-up. There are only the usual colors of various shades of gray between white and black, gold, red, and dark blue, in addition to lime green. That's why I hope that they will add light blue (preferably) and light green in the 2017 line-up.
OR by reducing performance. I am guessing most of it would come from increased battery/optimization, possibly adding DI and small aerodynamic tweaks like removing mirrors, more plastic belly pans and auto-hiding wipers. There will be stylistic clues to differentiate from non-ECO model
Just an opinion but Gen3 handling issues lie down in front tune up not lack of wishbone in rear. With proper set up twist beam rear is more than capable to outperform basic tires and shocks it will be fitted with.
Prius ECO could use Toyota TS040 Hybrid technology (AWD with SuperCapacitor) to rapidly get and give back all the kinetic energy.
These seem to be colors for the Japanese market . US and Europe will probably have different color choices.
Prius ECO could get solar panels instead of air conditioner to ventilate car under sun and charge LI-ION battery.
They will develop new LMP1 for the next year that will use batteries and have a smaller engine, current TS040 drivetrain is not competite against Porsche and Audi. There may be a bigger capacitor in the inverter to deal with short ms bursts of power, but I doubt it.
Mitsubishi had the guts to make one of their colours a reflective light purple. Very cool. I would not hesitate to buy a lime green if it was reflective. The "seaglass pearl" is a rather unusual colour. Some see it as light blue, some see it as light green. I think Pearl S is light blue most of the time, but with the sun at just the right angle and intensity it is "greenish". Looks light blue in my avatar <--. Solar panels wouldn't give you better mileage. They are very heavy. Due to the glass they need for protection. That's why the GIII with them has the 15" wheels, to try to keep the weight down.
Since currently Prius is only made in Japan, I doubt they have different color choices for different markets, in order to simplify the paint-shop operations. I will wait for 2017 Prius anyway, as 2016 Prius is the initial model year for Generation 4 and will have quite a few bugs to be sorted out, which will last at least until 2017. Toyota also typically introduces more color choices after the initial model year.
My '05 had the loose exterior b-pillar trim piece. There is always a greater risk of a purchased car having more problems the first year of being new or a redesign. The company's or previous model's reliability may also have no indication on how high the number of problems can be.
Found this on the internet. http://www.goo-net.com/catalog/TOYOTA/PRIUS/ Various Prius trim levels and special editions in Japan with various mpg numbers (note the change to JC08 in 2009, probably why the Gen 3 has the same number as the Gen 2). They had different colour choices for the Gen 3. For example, two colours were offered in Japan only - Iceberg Silver Mica Metallic and Aqua Blue Metallic