Oh I am sure it will go over 400hp for a chip, here is a small article on the ecoboost.
http://www.autoblog.com/2008/01/06/d...ect-injection/
I also believe there is an article out there (with video) of them describing the materials and assembly of the engine. As far as I know the TTv6 is only a $600 option on the flex as well. Not too much more for getting so much more over the base engine. I'm curious if they will make it that cheap of an upgrade on the Mustang...If they did, it will be a winner.