I heard all the warnings that they were pretty bad to see behind you. I ignored them and bought a set. Well, what do you know...I couldn't see well enough behind me. Now you can see when cars are comming up behind you, you just can't see what TYPE of car is behind you. Like say those with the little pretty lights on top that give you slips of paper and court dates.
They got removed in about 2 weeks of use and a couple of close calls. Regardless of where you put them, the problem is that they distort the image so you can see more to the side of you. With those with big shoulders, it will certainly help to move them out of stock position but unfortunately, long range distance is still always going to be a problem IMO.