The new Subaru WRX is like the preppy kid in school who can really let it rip on Saturday nights. Then there’s his bad-boy brother, the WRX STI, who’s rowdy all the time.

Subaru within two months introduced ’15 versions of both redesigned sports compacts. They share family resemblances, but their personalities differ.  

Both hold birthrights to belong to the performance-car clan.

The STI sports a spoiler; the WRX doesn’t. The STI rides on larger wheels (18-in. vs. 17-in.), and its badging is bolder.

Otherwise, the two cars share the same exterior styling, which includes a wide-body stance, crisper lines, a hood intake scoop and a new nose-cone front. The overall design looks more refined than the outgoing generations dating to 2009.

The main differences between the cars are driving dynamics and power. Neither car is wanting, but the STI is more powerful and aggressive. It should be, because it costs about $8,000 more. It’s the star athlete of Subaru, an automaker that prides itself on engineering above all else.

The WRX’s high-compression 2.0L 4-cyl. boxer engine features direct-fuel injection, a twin-scroll turbocharger and an intercooler. It produces 268 hp at 5,600 rpm, accompanied by a broad torque curve that peaks at 258 lb.-ft. (350 Nm) across a 2,000-5,200 rpm range. Torque tip-in comes quick and often.

The FA20 engine also powers the Subaru Forester CUV, but the WRX version uses different camshafts, higher-rate valve springs and other enhancements to extend performance and broaden the torque range. The WRX engine redlines at 6,700 rpm, compared with 6,000 rpm for the Forester.

The ’15 WRX comes with a new 6-speed manual transmission plus Active Torque Vectoring for improved agility. After a 5-year absence, the return of an automatic-transmission option on the WRX aims at broadening its market appeal. The CVT lets a driver using shifter paddles choose the equivalent of 6- and 8-speed gear modes.  

The track-ready WRX STI flexes more muscle than its sibling because of its 2.5L turbocharged and intercooled 4-cyl. boxer engine. It reaches 305 hp at 6,000 rpm and 290 lb.-ft. (393 Nm) of peak torque at 4,000 rpm. The engine is exclusive to the WRX STI.

The STI engine is based on a specially reinforced semi-closed deck block with high-strength cast pistons. That setup offers cooling efficiency when the driver is going full throttle, often the case with STI owners.

The STI’s exhaust system emits a distinctive growl through signature quad tailpipes. Engineers usually work to keep engine sounds from entering a car’s interior. But a level of “desirable” engine noise is pumped into the STI people compartment. It is music to the ears of STI buyers.

And that spoiler is functional, not just a fashion statement. It’s designed to generate stabilizing down force on a car with rally-racing roots. 

The WRX STI is equipped exclusively with a specially reinforced 6-speed manual transmission, which includes an STI short-throw shifter in the Launch Edition model. An automatic transmission is not an option. Nor should it be one for this speed racer.

So the STI wins the power contest, by design. It’s the most powerful engine in the segment which includes the Mitsubishi Lancer Evo and Volkswagen Golf GTI.

Subaru also bestows the STI with high-grade equipment for outstanding driving dynamics. That includes Active Torque Vectoring, an enhancement of the Vehicle Dynamics Control system, for improved cornering.

The turbocharger is under the engine of both cars. That low center of gravity does its part in contributing to driving stability.  Both vehicles offer that. They’re on a new platform offering a stiffer, more nimble chassis.

The chassis engineers really went to work, especially on the STI, making greater use of high-tensile-strength steel and stiffening elements at key locations. The result is incredible agility.

Improved steering responsiveness is a standout feature on both vehicles. The turning ratio is quicker on the STI compared with the WRX (15:1 vs. 13:1). But the sharper steering on both earns Subaru bragging rights. The automaker gladly accepts those. A Subaru engineer draws comparisons to the steering attributes of a Porsche 911. That might be pushing it, but not far.

STI at Home on Track

Subaru held California media previews for both models. STI drive-time included laps at Laguna Seca raceway near Monterey. It’s a twister course with a legendary hairpin turn. The STI gamely dives into it without breaking a sweat.

The WRX also enjoys life in the fast lane, although there were no racetrack hot laps for the press preview of this car. Instead, a driving route covered some of the Napa Valley region's most curvaceous roads. They almost were enough to make a driver dizzy, even before the wine-tasting later on.

But the car stays poised as it effortlessly enters one curve after another at reasonable but aggressive speeds. The WRX comfortably did those acrobatics mostly in third gear, not whining about it; instead relying  on its wide torque band.

Such gracefulness shows how far driving dynamics have come. Drivers doing hard-turn maneuvers like that 10 or 15 years ago would feel like they were in a canoe at high seas during a storm.

The cockpits of both vehicles are driver-oriented. The steering wheel is downsized a bit. Gauges are easy to read and enhance the overall design. Interior lines are crisp and work with each other.

Both cars offer SI-DRIVE that allows a selection of driving characteristics ranging from every-day to all-out. The former offers a more relaxed throttle response. It’s nice to have a choice for commutes and such.    

But in building such well-engineered cars, Subaru seems like it stopped at the infotainment systems. They’re about a generation behind. Screen buttons are so small, they’re hard to use. That seems like a Subaru trait across the lineup.     

The WRX and WRX STI appeal to pretty much the same demographic group, generally 30-something males. On the residual value front, Subaru says both cars are popular as used vehicles.

If you want great fuel economy, buy a Toyota Prius, not a compact performance car.

Estimated fuel economy for the WRX is 21/28 mpg (11.2-8.4L/100 km) city/highway. That’s with the 6-speed manual transmission. The STI’s estimated mileage is 17/23 mpg (13.8-10.2L/100 km) city/highway. No bragging rights there. All-wheel-drive takes some of the blame for the lower fuel-economy numbers. Still, AWD offers more advantages than disadvantages, and Subaru distinguishes itself by putting AWD on all its vehicles.    

STI pricing ranges from $34,495 to $38,495 for the Limited version. The base price is the same for the outgoing version.

The WRX starts at $26,295, about $200 more than the previous generation. Add $795 destination charges to both models.

These are delightful ready-to-rev cars from an engineering-centric Japanese automaker. The outgoing WRX, dating to 2009, carried the Impreza name, but Subaru dropped that moniker to make the new WRX stand out. It does that nicely.

Todd Hill, the STI’s line manager, describes the STI as “an everyday sports car; one you can use all the time.” You couldn’t say that about earlier STIs.    

About 10 years ago I drove one from Detroit to Chicago and back. You could feel every bump in the road, even on reasonably smooth surfaces of I-94.

Afterwards, I mentioned to someone that overall the car was pretty cool. Not knowing where I had taken it, he said, “Yeah, but I wouldn’t want to drive it to Chicago.”

I could make it there and back in the new STI without any complaints about the ride or much else, except for maybe that clunky infotainment system.

'15 Subaru WRX Specifications

Vehicle type 5-passenger, all-wheel-drive sedan
Engine 2.0L direct-injection turbocharged boxer
Power 268 hp @ 5,600 rpm
Torque 258 lb.-ft. (350 Nm) @ 2,000-5,200 rpm
Bore x stroke (mm) 86 x 86
Compression ratio 10.6:1
Transmission 6-speed manual/automatic
Wheelbase 104.3 ins. (2,650 mm)
Overall length 180.9 ins. (4,595 mm)
Overall width 70.7 ins. (1,796 mm)
Overall height 58.1 ins. (1,476 mm)
Curb weight 3,267 lbs. (1,482 kg)
Base price $26,295 plus $795 destination charge
Fuel economy 21/28 mpg (6-speed manual); 19/25 mpg (automatic) city/highway
Competition Mitsubishi Lancer Evo, VW Golf GTI
Pros Cons
Power on demand So-so fuel economy
Nicely done interior Very average infotainment system
Performance with comfort Limited customer base



'15 Subaru WRX STI Specifications

Vehicle type 5-passenger, all-wheel-drive performance sedan
Engine 2.5L direct-injection turbocharged boxer
Power 305 hp @ 6,000 rpm
Torque 290 lb.-ft. (393 Nm) @ 4,000 rpm
Bore x stroke (mm) 99.5 x 79 mm
Compression ratio 8.2:1
Transmission 6-speed manual
Wheelbase 104.3 ins. (2,650 mm)
Overall length 180.9 ins. (4,595 mm)
Overall width 70.7 ins. (1,796 mm)
Overall height 58.1 ins. (1,476 mm)
Curb weight 3,386 lbs. (1,536 kg)
Base price $34,495 plus $795 destination charge
Fuel economy 17/23 mpg city/highway
Competition Mitsubishi Lancer Evo, VW Golf GTI
Pros Cons
Awesome power So-so fuel economy
Nicely done interior Very average infotainment system
Wonderful driving dynamics Not for the faint-hearted