A little late here with this post. If you haven't already jumped into the deal I would suggest that you go with the original towing mirrors. I have them and I really like them. I did use some strap ons and really didn't like all the fuss. Adjusting them manually was a pain and they did have a tendency to vibrate.
I ordered them as part of a package when I bought my '08. I don't know what is available today but I would try to get them installed first. If that isn't possible the aftermarket ones someone posted would be my second choice. Stay away from anything that has to be strapped on.