Picking powertrains used to be simple: straight-six or V-8?
But consider the all-new 2013 Ford Fusion mid-size sedan that reaches dealers this fall: It comes with a base 2.5-liter four-cylinder engine, or you can pick from a choice of two different smaller, turbocharged EcoBoost fours, in 1.6- and 2.0-liter sizes.
Then there's the 2013 Fusion Hybrid, and a new entry, the 2013 Fusion Energi (available later this year).
The Energi is a plug-in hybrid, which shares the hybrid's running gear but uses a larger lithium-ion battery pack in the trunk that will let you plug the car into the wall to recharge it--and give you up to 15 miles of all-electric range, after which it reverts to being a conventional hybrid.
Which one to pick if you're interested in fuel efficiency?
The main high-volume choices are the Fusion Hybrid or the Fusion 1.6 EcoBoost. And comparisons can get tricky quickly.
The 2013 Ford Fusion with the 175-horsepower, 1.6-liter EcoBoost engine and six-speed manual transmission delivers 29 mpg combined, according to Ford. The six-speed automatic comes in at 28 mpg.
That engine can also be ordered with an optional $295 start-stop system that switches the engine off when the car stops, then back on as the driver lifts a foot off the brake.
Ford says the start-stop option gives an overall fuel-efficiency boost of about 3.5 percent, but that owners who drive mostly in cities may see improvements up to 10 percent.
A reasonably equipped Fusion SE with the 1.6-liter EcoBoost automatic, navigation, blind-spot monitors, leather seats, a rearview camera and rear parking sensors comes in at just under $30,000.
The 2013 Ford Fusion Hybrid is a higher-spec model, with some standard features that cost extra on the Fusion 1.6. It is rated at 47 mpg combined (47 mpg city, 47 mpg highway) and starts at $27,995 including destination.
While it's far more price competitive than the hybrid 2010-2012 model, it's still likely to go out the door with a sticker around $33,000 by the time all's said and done.
Which to choose? Part of it will come down to how you like to drive--and where.
2013 Ford Fusion Hybrid, New York City
The Fusion Hybrid is at its very best in urban stop-and-go traffic, where it has enough electric power to run short distances--and creep forward in traffic--on electric power only.
The efficiency difference between city and highway running is much smaller than it used to be, though. The Fusion Hybrid's triple 47-mpg EPA ratings indicate that Ford has achieved a real balance between the two modes, so--pending a road test--we expect it to return real-world fuel efficiency in the mid-40s.
The EcoBoost 1.6 costs you less to buy, but more each year in fuel costs.
Driving 15,000 miles a year in a 29-mpg Fusion 1.6 would cost you $2,068 if gasoline costs $4 a gallon; the 47-mpg Fusion Hybrid would only cost you $1,276.
If the two cars are priced $3,000 apart, that's a payback period of just under four years--lower than the period for Ford's earlier hybrid models.
In the end, either car will give you vastly better fuel efficiency than the mid-size sedans of only a decade only. The change is mostly spurred by gas-mileage rules, as well as Ford's decade of experience developing hybrid powertrains.
Are you willing to pay a little extra up front for class-leading fuel efficiency in a mid-size sedan? Then the 2013 Fusion Hybrid is your car.
Or are you comfortable absorbing higher fuel costs each year for a lower purchase price (or, more likely, a lower monthly car payment)? The Fusion with the 1.6 EcoBoost may be your best bet.
There's also the larger 2.5-liter base engine, rated at 26 mpg combined, which is cheaper yet, but mostly aimed at fleets.
Ford talks a lot about "the power of choice," and the sales of the new array of Fusion models may give us a much clearer picture of how consumers value fuel efficiency versus cost.
The balance will tip toward the efficient models, of course, the next time gas prices suddenly spike.
But we don't see any bad choices here, and we recommend you drove both models to see if the smoothness of a hybrid appeals more than the conventional engine-and-six-speed-automatic driving characteristics of the EcoBoost model--with or without the start-stop.