On GM vehicles, it's 5% of MSRP that is considered a "taxable fringe benefit" when you use the employee discount. Not quite as bad as the whole thing being taxed (since your tax consequences on a $25k vehicle you get a $2k discount on are only $1250), but still a consideration.
$1250 taxable = What $300 to $400?
The discount is worth 4 to 6 times that using your numbers.
Still not shabby.