I dont think 4ohm 8 ohm 16 ohm are the better or only choice. Just a choice and a quality loudspeaker can be made at 4 8 16 ohm without any real issues but of course you need to select amp and loudspeaker that work well together. So the Ohm loads not much of a design issue more of a system matching issue. But for hi-eff I shoot for 16 ohms. for med 4ohms is fine and I offer 2 4 ohm models. As for the rest this thread puts a hurt on me brain so good day.