Speaking as a publisher (which is what I do for a living) who sells wholesale to Ingram, who then resells to Amazon.com, I can safely say that the price that Amazon.com is offering is wholesale + 2%. You won't do any better on a group buy from the publisher.
That's too bad. It would be fun to get a few hundred of us lining up for the book I guess Amazon it is!
I got the book today. All I got to say is every boxster owner should own one of these if they do any work on the car or just want to know more about it. I would've paid 3 times what I paid. It even covers engine removal! Great book.