I have a Model S but FWIW 1. Nil problems but a sunroof would improve ventilation. I find i need to use AC more without one 2. 100%. Literally. Current one is 13 months, last two (for four years)- only a blocked windscreen washer hose in one. 3. Only when you see it on the website- usually as a ploy to promote sales. Supercharging is less than 1% of all charging. 4. No. When I bought my third they still wouldn't come down in price. 5. N/A All the best!