Last year's improved performance for the WRX was enough to satisfy most reviewers, who had mostly good things to say about the way this sport sedan or hot hatch handles. Meanwhile, the STI's even more impressive performance places it in contention with many more expensive vehicles.
With any sports car, the engine is only part of the story, and this is especially true in the case of the WRX and STI. Subaru engineers have done a sublime job with the suspension tuning. Despite the thicker anti-roll bars and stiffer springs introduced last year, both the WRX and STI soak up bumps, ruts, potholes, and coarse surfaces with aplomb. The ride is beautifully smooth and isolated; the handling is wonderfully direct and taut. At highway speeds, apart from a little engine rumble and wind noise from the side mirrors, things are very quiet in the cabin.
The 2010 Subaru Impreza WRX is much more powerful than the previous models, which Edmunds reviewers attribute to "a larger, STI-based turbocharger, wider-diameter exhaust and less restrictive catalytic converter." Cars.com finds that the engine on the Subaru Impreza WRX is a "265 horsepower, turbocharged 2.5-liter four-cylinder with 244 pounds-feet of torque," and most reviews read by TheCarConnection.com are positive in regard to the powerplant. Upgrading to the STI model gets owners a "305 horsepower, 2.5-liter H-4," according to Cars.com. Reviewers point out that both engines need to be revved hard to get the most from the engines, with Jalopnik noting that "below 4,000 rpm, you've got nothing, but above that it flies." Car and Driver agrees, advising that, "for max power, the revs need to be above 4000 rpm." Acceleration times for the 2010 Subaru Impreza WRX and STI are impressive. Motor Trend reports that "sixty mph comes in 4.8 sec, and the five-door, five-passenger hatchback we tested covered a quarter mile in 13.5 sec at 101.1 mph." The Subaru Impreza WRX STI is slightly quicker on both counts, thanks to its extra 40 horsepower.
While there’s much praise for the engines in the 2010 Subaru Impreza WRX and STI, the same can’t be said for the transmissions, which disappoint most reviewers. The Impreza WRX is available with a five-speed manual or an optional four-speed automatic, while Cars.com points out that the Subaru Impreza WRX STI is available exclusively with a "six-speed manual w/OD." Jalopnik reviewers report that the transmission is "notchy, requiring a firm, accurate throw," although the "clutch is surprisingly light." Motor Trend laments that "the biggest shortcoming is the shift linkage" for the regular Subaru Impreza WRX, although ConsumerGuide praises the Subaru Impreza WRX STI for the fact that "its shift and clutch action are smooth and precise."
A strength of both the WRX and STI is a symmetrical all-wheel-drive system, but unfortunately, the added traction comes at the cost of fuel economy. Car and Driver warns Subaru Impreza WRX STI owners to expect "frequent fill-ups," and regular WRX owners should take notice too. According to official EPA estimates, the Subaru Impreza WRX should return 18 mpg city and 25 mpg highway, while the Subaru Impreza WRX STI gets just 17 mpg city and 23 mpg highway.
The handling of the previous Impreza WRX is criticized for sacrificing too much for the sake of ride comfort. That, however, is corrected with the latest generation, as Edmunds reviewers point out that "beefed-up spring rates and stabilizer bars help” the WRX and STI when it comes to steering accuracy. Jalopnik reports that performance imports like the WRX and STI are "ultimately extremely capable, but pushing it hard initially requires an unnatural level of trust as the chassis lacks that nth degree of feedback." Edmunds also points out that the 2010 Subaru Impreza WRX’s and STI’s "steering, while precise, could stand to gain a bit more resistance and feedback." Ride quality isn't great, but Cars.com does note that the Subaru Impreza WRX "offers better everyday liveability than Mazda's performance hatch," although ConsumerGuide mentions that the "STI is expectedly stiff and occasionally jarring over bumps."
In terms of stopping power, few cars in this segment are better than the Subaru Impreza WRX and STI. ConsumerGuide says that "stopping control is very good on all models," while Jalopnik describes the brakes as "competent and confidence inspiring."