I've avoided these, but my son bought one on eBay that said it was a factory service manual on CD. I have something like that for my Saab, so there were no immediate red flags.
But when it arrived, we found that the person had just scanned their manual into PDF format, and copied that file onto a disk. The copies were legible, but low quality.
Perhaps technically correct, but certainly not what either of us expected.
It wasn't a lot of money, so rather than getting into an e-battle with the seller, we chalked it up to an eBay learning experience.
Since then I've spend the money to get the real deal from the dealer or a reputable seller.
Good luck.
Jay