V8 over V6 if not towing?....Other than it's effortless power w/8 speed trans....no other real reason especially if FE is of more importance.
I find the V6 8-speed combo plenty peppy for everyday driving.
Now personally I would not buy 2012-2013 V6 as I found it a dog...I'd only consider the Hemi in those years.
2014 was first year of the 8-speed...and was also a mid-cycle update both inside and out and with all the updates, I would just focus on a 2014-2015 model year.
Real world V8 mileage w/2wd 17 mixed...21-23 highway depending upon your cruise speed. 12-14 city only.