I posted this in the new member area but was not getting any responses so I thought I would try here...

New member here.
I'm in a bit of a dilemma and thought I would reach out to current owners. I'm buying a new (used, but new to me) car and have narrowed my search down to a 2014 Mazda 6 Touring with 39,000 miles for $13,900; or so I thought... Very brief bio on myself first though. I am married and have two small children and live in Central New York. My current car is a 2005 Subaru Impreza which has served me very well for nearly 10 years. I am starting a new job in a month and will be commuting 70 miles one-way (highway), and using my vehicle frequently for work as well; its time for a new car! My Impreza has been great and my 6'1 frame was never uncomfortable even though the car itself is small. As my family has grown, I swore my next vehicle would be a larger sedan or (gasp!) a crossover (I'll never go minivan no matter what).

I have been very pleased with everything I have read about the Mazda 6 regarding fuel economy and overall cabin space; as well as the look of the vehicle and the 2.5 liter/184 horsepower engine.
Here's my problem. I was initially uninterested in the Mazda 3 because it appeared smaller than the Mazda 6, and as I stated earlier, I have wanted to upgrade to a larger vehicle. As I did more research however, I found that the 6 and 3 have identical cabin specs, and the overall length of the vehicles is actually not much different. A few hours ago on a whim I searched online and found a 2015 Mazda 3 Grand Touring trim for $13,900 with only 36,000 miles; this Grand Touring is the 2.0 liter/150 horse power engine, not the 2.5 liter.

I have done a fair bit of research on comparisons of the two vehicles, but nothing of substance has really come up. I'm looking for real world advice from real drivers. Will I miss the pep and horse power of the 6 if I go for the 3? I feel like I would be crazy not to consider the 3 since it is the higher trim level, a model year newer, and has fewer miles, all at the same price as the 6. Pep and acceleration will be very important to me since most of my commute will be spent on the thruway; averaging 75 mph.
Finally, I fully plan to test drive both vehicles, but I don't think this will give me the overall picture of daily driving each vehicle over time. Thanks in advance for any advice!