Sorry, but that comparison will not work in all situations.
where{$_.FreeSpaceGB -like "8*"
PowerShell will convert the decimal into a string, and the where-clause checks if the 1st character of that string is 8.
That means that "8","80","800" ... will all match, which is probably not what you want.
The correct condition is (like I showed before)
where{$_.FreeSpaceGB -ge 8GB
