Matrix,
In answer to your first question, yes, Sport Mode allows the battery to deplete to 26 miles even when it starts at 50. Which is why I don't drive Sport until it hits 26 or below, normally. I think I mentioned this next things elsewhere too, but the Energy Flow screen shows the battery consumption/generation from what I can make out, so that when you floor it you see -180+/-1 kW. In Sport mode when floored, it flucuates a lot more, but bounces around the -130 +/- kW range, which would lead me to believe that the generator is giving about 170kW to offset and make the 300kW max out of the motors.