I agree, referring to the cars as 100-4 and 100M is shorthand, especially if you don't know your audience, I owned a 100 for a while, sorry if it offends but I often referred to it, I know the correct term was 100 and 100/6, but not evryone does, and for those that know less it saves the trouble of the next question "4 or 6?"
I knew what d valentino meant when he said he was coverting it to M spec, or Le Mans spec if you really prefer, I don't see what all the fuss is about, he stated as much and quite frankly sometimes I think the people that like to make a fuss about it sort of want to show off that they know more about Healeys or british cars or whatever, am totally against a car being misrepresented in a sale, but using shorthand references to convey meaning, especially when you don't know your audience isn't really something to get worked up about, having said that maybe getting worked up about people getting worked up about it is just as silly.....
Great looking Sprite, think I have seen it in a couple classic car mags?