Rock protection has proved to be important for the painted Montanaas (Big Skys). There has been lots of discussion about the various options. Rock Tamers are a popular choice and are most effective for SRW trucks. You can do a Search on "Rock Tamers" and learn much more. Here are a couple of topics I found that may interest you.
http://www.montanaowners.com/forums/...ms=rock,tamers
http://www.montanaowners.com/forums/showthread.php?t=50245&SearchTerms=rock,tamers