What are the odds that dealer could flash computer on 2011 LTZ so DIC would show instantaneous fuel economy? That is one thing I really miss from the CTS I traded for the Cruze.
If the DIC computer is the same between ECO and LS/LT1/LT2/LTZ, then it all comes down to whether 1) GM has given the dealer an option to update the software and 2) whether the dealer will do it. My Boxster has lots of DIC options that you had to buy, and dealers did not want to turn them on for customers not buying them up front. Thanks to aftermarket tools, the dealer can be ignored in the process and we turn them on for new owners at our annual hack day / track day event.
Aftermarket scan tools show the data is available from the ECM. I tested a ScanGauge device that pulled the data right from the ECM. Another manufacturer, Auto Enginuity, had a bluetooth device that would send the data to your Windows Mobile phone application. Too bad they picked Palm and Windows Mobile and not iPhone or Android as the first apps they support.