I just installed one of these kits on my '11 Mega-cab, and I did it by myself... with no help in 1 day of downtime.
A couple of important notes about the installation and use...
1-Make sure you empty the tank as far as possible to make it as light as you can get it. Try carrying a fuel can and keep on driving until it indicates no fuel range left, then drive some more. The extra fuel can will ensure that you don't get stranded if you guess wrong. I drove until I used up all the miles indicated on the DTE (distance to empty) indication. When I dropped the tank, I still had about a gallon and a half in it, but I don't know how much of that could have been used.
2-Remove the left rear fender liner to access the filler and vent hose connecting clamps.
3-Pop loose the fuel lines from the clamps on the frame for about 3 clamps to give sufficient flexibility in the lines to allow the tank to be lowered as far as possible to reach over the top of the tank from under the truck to disconnect the fuel lines (2) and the electrical connector.
4-Use a couple of inverted 5 gal. plastic paint pails to help lower the tank down after the 2 tank clamps are removed. A couple of additional spacer blocks of shorter height will also be helpful in lowering and raising the tank.
5-While the tank is down and you are cutting the hole for the new vent fitting, go ahead and empty the tank to make it even easier (lighter) to reinstall.
6-Plan on making MANY trips under the truck and back out again during the removal/installation process.
7-Mark the location of the locking ring and the fuel sending unit with tape and a marker or using a paint marker before removing the unit.
8-Make sure you use a small cottage cheese container on the inside of the tank when drilling the hole with a hole saw. Make sure you use a hole saw of the recommended size rather than drilling a smaller hole and then using a Dremel or a file. You don't want to make any more shavings or junk than absolutely necessary.
9-The tank was able to be pulled out from under the truck without using a jack to lift the body, but I did have to use a jack to gain a couple of inches to put the tank back under the truck [I have a 4WD, so it is higher than a 2WD truck].
10-After you get the kit installed, till-ups are much quicker as advertised. The kit works well, but remember this when topping off: DO NOT TOP-OFF IF YOU ARE NOT GOING TO DRIVE ABOUT 15 OR 20 MILES! Fuel will be pumped-in cold (or cool), and when it is in the tank, depending on the temperature, it will warm-up and expand. If you fill-up and then let the truck sit, IT WILL LEAK! That's because the expanding fuel has nowhere to expand to except a point of least resistance, and ultimately a puddle under the truck.
About the extra fuel that you could expect to get into the tank after you install the kit...
My factory tank is stated to hold 34 gallons. After the kit was installed I was able to put in 39 gallons…from dry empty to full/full.
I purchased mine from the website referenced in this forum, and would recommend the source and the installation to everyone I talk to.