I purchased some of the guards from ********** also. I think they are a perfect compromise between protection and how far they stick out (I'm not going for the rally car look). Instructions were included but it's a pretty straight forward mod. I also used the 3M molding tape, cleaned surfaces with rubbing alcohol and everything sticks great. I ended up using the retainer clips anyways as insurance, but when I had just the 3M tape it held very firm. I feel much better now knowing that I am NOT sandblasting the sides of my car anymore.
This is definitely the way to go if you don't want to spend over $100 for a $7 part that has been cut up, but you also may be lazy (like me) and don't want to spend the time measuring, shaping, cutting, and drilling. I chose to go the ~$50 route, which is my limit between buying a finished product and doing it myself. I honestly do not know why anyone would spend over $100 with this option available to them.
I bought the 3M tape from Walmart in the automotive section. I checked with the local Target and Home Depot first, but they did not have it.