The changes to the Ecotec for 2007 include a new ECM and new ignition system. The ECM is now a 32-bit E37 unit.
That's great and all, I think it will be alot better. But please HPT, don't leave us 2005 and 2006 E16 users out in the cold. I would hate to have to buy a new 2007 Cobalt just so I can tune it.