When he hits arbitration after the 2007 season, it will be the first time Teixeira can request a salary commensurate to his peers. Carlos Delgado would be a good match; I would expect Boras to ask for $14-15MM at that time. PECOTA sees Teixeira as a $20MM player annually through 2011, so it will be money well spent.
Whether Texas will commit the $100+ million contract Teixeira will require after that remains to be seen. Jon Daniels seems to be on decent terms with Boras, with recent signings of Eric Gagne and Kevin Millwood.