[Xperia Z3v General] Jfaluty:
Following the thread instructions is useful, but I want to show the steps I went through to potentially help others. At the time, my Xperia Z3v is on 5.0.2. I assume you already have ADB working on your Windows computer.

(Optional) I personally decided to factory reset my phone before this process.

Download the pre-rooted firmware from the link provided in first post of this thread (much thanks to their efforts!) to your device, and remember where you put the file.

Install KingRoot from their website or XDA post. At the time of this post, the newest version is v4.8.5.

Open the app and have KingRoot root your device. It might try and install its "Purify" app. It isn't needed for this process. Don't do anything else with KingRoot after it roots your device. The next following options are about removing KingRoot for a different superuser. If they do not work, don't worry, installing the firmware in the end will remove KingRoot.

(Optional) Download a root checker from the Google Play store to verify root.

(Optional) Download SuperSU or Superuser from Google Play and install the binary. I attempted to use SuperSU, and selected to have the binaries install through the Normal method (Not TMRP). It detected that another root access app was already installed (KingRoot), and asked to have it uninstalled. I selected yes, BUT it did not work for me.

(Optional) Some have used the app Super-Sume Pro from the Google Play Store. I was not able to get this to work either, however it has worked for me in the past.

Download the XZDualRecovery on your computer from the provided link in the first post of this thread. Use the Z3 version. At the moment, the newest version is 2.8.26 release. Unzip the download into its own folder. In Developer Options on your Xperia, enable USB debugging. Plug your Xperia into your computer and (if you haven't already) authorize your computer.

Open the folder on your computer that contains all the files you unzipped (the XZDualRecovery). In the folder, there should be a file named "Install." Open that file and your Command Prompt should appear with a six different choices. Select the option that says to install the recovery on a rooted ROM with SuperSU (I think it is choice one).

Let the command prompt run and selected "any key" when it asks you to. Once it is finished, your device should automatically boot into recovery (TeamWin). It it does not, unplug your device and download an app on Google Play that offers different power options.

Once in recovery, install the 5.1.1 pre-rooted firmware that you downloaded earlier (again, thank you to the contributing members!). Once the flash is complete, reboot your device.

Finally, when the device powers on, it should optimize all the apps. You will also find that KingRoot is gone, and was replaced with SuperSU.

If you have any questions I might be able to answer. Thanks again for the files provided in the thread.

Thanks...

@zxz0O0, "for achieving root for our Z3v"

@jal3223, "for helping me as much as you can to guide me through myself"

@[NUT], "for the custom recovery to install onto our Xperia devices"

@GigaSPX, for the original post and host of files