I have always thought the 126 should be a single wiper system, it very nearly is, the passenger side wiper covers such a small swipe that I doubt anyone would miss it if it was not there. the driver's wiper has SUCH a huge swipe, and it works so well, I totally see where the 124's system was derived. a smaller windshield, so that small amount the 126 wiper missed is removed from the car! I've not driven my 124 in the rain much yet, and my wiper has the wrong blade on it, so it's bound in the corner. I'll have a verdict on the mono/double of my own.