Are the aerodynamics that different between the 300 and Charger, in which the Charger had an advantage in regards to fuel economy with the eight speed transmission. Haven't looked thus far, but are both utilizing the 2.62 rearend, or is that gearing different with the eight speed transmission now?

 

I dont think Charger has better fuel economy. They are also identical in terms of under the hood and electronic wise.
maybe u are looking at the 5 spd base model 300 instead?