Awesome Repost from Car and Drivers Review of the Subaru STI.
If competition improves the breed, then the corollary is that the lack of competition invites stasis. And the Subaru WRX STI has only one natural predator: the dead-car-rolling Mitsubishi Lancer Evolution, the product of an enterprise that seems a little on the fence about whether it wants to sell cars or get deeper into the uranium business.
Thus the new 2015 WRX STI isn’t as new as it might be if it had any real rivals. Most of the improvements went to the chassis, which was pretty excellent to begin with. Meanwhile, the one glaring deficiency—power—was once again tabled till the next meeting.
But, oh, what a chassis. The latest STI is stiffer, both in terms of the body structure and the suspension. The steering is quicker than the regular WRX’s, requiring only 2.5 turns lock-to-lock versus 2.8. The “Super Sport ABS” Brembos can adjust brake pressure at each rear wheel while cornering, so if you’re trail-braking into a corner you get the sensation of off-throttle torque vectoring. Of course, you also get on-throttle torque vectoring via a brake-based system at the front end. The STI hates understeer.
Healthcare professionals will be amused by the center-console rocker switch labeled “C.Diff.” In medical lingo, C. diff is shorthand for Clostridium difficile, a bacterium that causes explosive diarrhea. In the STI, C.Diff causes explosive corner exits, depending on how much lockup you demand from the center differential. The default torque bias skews aft, with 41 percent front and 59 percent rear. Both the front and rear ends use limited-slip differentials. Traction is not a problem.
For all the STI’s power-allocation magic, it’s overdue for more power, period. The 2015 STI brings 305 horsepower from its 2.5-liter flat-four, just five more horses than the first U.S.-spec STI had back in 2004. A decade ago, 300 horsepower was impressive. Now you can buy Jet Skis and four-cylinder Mustangs with more than 300 horsepower. The world moves on.