I tow with a toyota tacoma, so I have been down this road. I first bought the Tow-N-See mirrors (Amazon.com: Horst Dynamics Inc. Flat Tow 'N See™ Mirror: Sports & Outdoors
). They say on just fine, but I noticed in windy conditions that the mirror extension would cause my truck's side mirror to move within the housing (a little popping noise at the servo). It would get frustrating having to rolling down my window and popping it back in place while driving down the road. It would happen most often when being passed by a semi.
I researched and bought the McKesh (McKesh Mirrors
) srap on mirrors. These are much more superior, very stable. My only complaint is the white strap color. Not sure why they couldn't go with black or something. The go on/ off the truck super fast. I highly suggest them.