That's great info about ProduKey now getting the product keys from the BIOS.
Here is some more info regarding installing 8.1 straight to a computer when there is a HD failure and a Win8 key.
https://www.technibble.com/forums/threads/install-8-1-with-8-product-key.53584/#post-412065
We modified the ei.cfg file on the installation USB so it doesn't ask for a product key when you install 8.1. It installs 8.1 which bypasses the lengthy 8 to 8.1 update process. Once 8.1 is installed, then you can run ProduKey or RWeverything to get the product key and enter it in and activate.
Ideally though, just make a Windows 8.1 image in VirtualBox. Run sysprep on it. Inside the VirtualBox environment boot to a Macrium Reflect CD and create an image of Windows 8.1 in Macrium Reflect. Now anytime you need to install 8.1 to a HD, just boot to the Macrium Reflect CD on the computer with the new HD and restore the 8.1 image. We use DriverPacks afterwards to install all the drivers. DriverPacks is a 4+ GB download of many common drivers. It will normally find everything and has a nice installer that is automated so there isn't too much interaction with it.
The great thing about using Virtualbox is that you can just keep that image there without bothering it. When Windows Updates get 30-40 new ones you can update the Virtual Box instance and then make a new image in Macrium Reflect.
It takes us less than 6 minutes to restore an 8.1 image to a new computer. With drivers add another 6-7 minutes. Then we will go through and install some essential software. 7zip, CCleaner, etc. In total it is less than 30 minutes to install Windows 8.1 with all updates, drivers and essential software.
Using the 2 methods above will take the headache out of any Windows 8 installation.