As we pointed out in our first drive of the 2015 Subaru WRX STI, the WRX itself is one heck of a tough opening act to follow—especially just in terms of performance value for the money, with its base price of $27,090, including destination.
As for the STI, it starts about $8k higher than the WRX, but it adds more standard equipment, and becomes a considerably more serious performance car.
Of course, the WRX—which we've just given full coverage with a 2015 Subaru WRX video road test—has become a more serious performance car this year, too.
Luckily we were able to drive the WRX less than a week before heading out to drive the new 2015 STI, so we had a decent baseline by which to gauge the STI's superiority. But the WRX had us almost fooled that we were in an STI; we were surprised at how firm the suspension is tuned, how vivid and strong the powertrain response is, and how 'in check' this small sedan feels dynamically, at all times.
Vast differences in performance—and WRX holds an edge in drivability
And then there's the delightful surprise: that the WRX's new direct-injection turbocharged 2.0-liter 'FA' flat four, making 268 hp, manages to feel a lot stronger than the old WRX where it counts—in the middle of the rev band. You could become a little lax in shifting and be caught in a gear too high, and the whoosh of boost would seemingly erase any worries of bogging down (and the paddle-shifted CVT, we hear, does a very good job pretending it's a dual-clutch). Subaru, by the way, says (typically very conservatively) that the WRX can get to 60 mph in 5.5 seconds, while the STI can do it in 5.1 seconds. But trying to squirt into a gap in traffic, without being super-vigilant about revs, you might actually judge the WRX the stronger.
Technically, that's not the case. Opt for the STI, and you get the carry-over EJ-Series engine, making the same 305 horsepower that it's made for years, but fitted with a Sound Creator that brings more intake-generated noise into the cabin, in a controlled way. Again, after driving the WRX, it was abundantly clear that while the STI might be everything it promises to be when revved into its upper ranges, its torque curve isn't nearly as robust, and it's not quite as forgiving (a difference just thoroughly dyno-tested and explained by Road & Track).
The gearboxes for both models might look the same at a very quick glance, but the WRX gets a cable-shift linkage for its lighter-duty six-speed transmission while the STI gets a heavier-duty gearbox as well as a more precise (and expensive) close-ratio unit with parallel-rod shift linkage—and, in the Anniversary Edition cars, a short-shift kit.
WRX clearly does more with less
Over our time with the WRX on roads around Portland, we were very impressed (and surprised) to see that we'd returned 25 mpg over 160 miles of varied driving—some of it very spirited runs on a favorite mountain road. On the other hand, in the STI (only in aggressive driving, admittedly), we averaged around 17 mpg.