are you set on getting the 2LS? the lower diff ratio will make the car slower on acceleration and the automatic transmission will reduce your power output at the wheels even further.
if you aren't completely determined to get an automatic, maybe you should consider getting the 1LS. the higher diff ratio and more efficient transmission will help the car feel and run faster. having a stick-shift will also allow you to enjoy your mods even more.
also, i still haven't seen any confirmation as to whether the 2012 V6 camaros have a flash counter, but if they don't or you aren't too concerned about the powertrain warranty, a tune will also give a nice little power boost, especially if you get the 2LS. on the automatic, the tune also optimizes the transmission to give the car a much sportier feel and better/faster shifting and better shift-points. that will make a big difference, since the automatics like to keep the RPMs a bit too low and the tune fixes the car from shifting into too high of a gear too soon. i can only imagine that effect would be worse on the 2LS, due to the lower diff ratio.