On the noise question Hear Hear! I have never understood why it is so low on the list of design priorities. Here in crowded Europe most of the opposition to aviation is because of noise, and it is opposition which can close airports and even air force bases. It does not help when departure / arrival procedures agreed to reduce noise are ignored as happens 10 percent of the time in places like Bordeaux... Diamond at one point was working on a surveillance version of its twin, which with relatively simple measures like sound insulation around the engines, better mufflers and new prop designs could not be heard from the ground when at 2,000ft. Noise regs in Germany already make it hard to operate aircraft like the Cessna Caravan, so maybe, someday, engineers will rewarded for making aircraft quiet.