This is my second Undercover. I had one on my Tacoma DC Prerunner. I sold that truck to get this Tundra. I put a new undercover on it within a week or two of buying the truck. They are the best bang for your buck IMHO. They are also indestructible.
You can order one that installs on a Tacoma or Tundra without the deck rail system. Check around your local dealers. My Line-X dealer cut me a deal to get the bed sprayed and the Undercover tonneau at the same time.
See photos below.