FYI, I don't believe the 2.1 is 7000 series aluminum, at least not for 2011. Their website shows the 2.1 as using "Alpha Black Aluminum" which is described as:

"Trek’s high-performance aluminum alloy, Alpha Black is 6000-series aluminum that has been hydroformed or mechanically formed to optimize the tube shape and butting profile. Alpha Black frames may be smooth welded for aesthetics."