The eBay workshop manual is just a RIP of the full GM Workshop Manual DVD.
It has some bits missing when compared to the full Version.
I bought the full Genuine GM DVD version from US ebay for around $100Au around 1 year ago. (DVD with roughly 4 Gigs).
It has every, and I mean EVERY GM vehicle version from 2007 to 2010 and some older models as well. This includes Holden, Chevrolet, Pontiac, Buick, Cadillac, Daewoo, Opel, and Vauxhall.
The official version is good in the sense that everything is cross linked with one another.
It has an inbuilt web server, that serves the pages up using an inbuilt search engine.
I have seen the eBay version and that version has had most of the Pontiac G8 pages saved as PDF. It is still missing lots of information (Because the GM workshop manual is not sequential like a book, it is difficult to get EVERYTHING from it).
The eBay version has also been available on torrents if you are so inclined to look.
Your best bet if you are serious is to search eBay US for the GM workshop manual DVD. Get the real deal !!!
You will NOT be disappointed if you can pick it up for less than $100Au