I just got (received today) a set of OEM towing mirrors for my 2001 Suburban. They were $110 for the pair on eBay. They are the same mirrors as a Silverado and are going to look really big on a Suburban. I tried a pair of CIPA mirrors and they were kind of so-so for me. I tried another add on mirror a few years ago that vibrated so bad it was like having a disco ball outside your window at night time from the headlights reflecting off them. I don't think towing mirrors are a necessity but they sure are a nice feature to have in traffic especially if you don't have a passenger to give you that extra set of eyeballs and right side perspective.