I don't want to say you are wrong about the SID, because technically you are not, but the article you referred to makes a gigantic distinction between the Machine SID, the Domain SID, and other unique identifiers. I am working with a Veeam full backup of an established Windows 2008 R2/SP1 (64-bit) server running Microsoft SQL 2008 R2/SP1. The article states the following:
"The Microsoft-supported way to create a Windows installation that’s ready for deployment to a group of computers is to install Windows on a reference computer and prepare the system for cloning by running the Sysprep tool. This is called generalizing the image, because when you boot an image created using this process, Sysprep specializes the installation by generating a new machine SID, triggering plug-and-play hardware detection, resetting the product activation clock, and setting other configuration data like the new computer name. "
The article is not stating that NO SIDs need changed, but that the Machine SID (which the "newsid" program that the author created modifies) does not need changed. Microsoft has taken the position that the only supported method of cloning a computer is to use the sysprep utility. Since Sysprep resets many configurations on a system to their default state and changes the way the "cloned" computer behaves, I would not end up with the test system I desire, but with a blank slate that could then be used to create the test system. Sysprep is also only supposed to be run on machines that are not joined to a domain.
This still leaves me wondering what the actual "supported" method/procedure is for restoring a working VM as a duplicate test server...