Any Impala with the 3.9 (LT2,LTZ) and of course the SS had dual exhaust from 06-2011. In 2012 all Impalas have standard dual exhaust and the 3.6 dohc vvt di from the Camaro. I had one of those as a rental last week when my GXP was in the shop and its peppy for sure. 6 speed auto keeps the revs high where it likes to be. Great gas mileage from the 3.6 btw.