Tech Tips: 2015-'18 Subaru WRX

These cars are more neutral-handling than any previous WRX, and they make perfectly competent autocrossers right out of the box. For the tight courses, though, some of our customers like the back end to be even more lively. Upgrading the rear sway bar using a Mach V-brand 22mm kit is an affordable and popular way to get the rear end to move around more readily.

Rally Armor mud flaps are really popular, especially for owners who drive on unpaved roads a lot. Four driven wheels makes for a lot of road debris thrown up along the sides of the car, so the mud flaps protect the paint and help keep the car cleaner.

Another common low-buck upgrade is a set of Hella Supertone horns. The stock Subaru horn kind of sounds like a cartoon road-runner–and not a very loud one. The Hella horns turn up the volume and sound more assertive.

The cable-actuated WRX transmission on the manual cars doesn’t have great feel. A short-shift adapter like the Kartboy Short Shifter helps to tighten up the feel and shorten the shift throws.

These cars are pretty reliable, and so far they don’t really have any obvious weaknesses. The FA20 turbo engine doesn’t seem to have quite as much headroom as the older EJ25 motor in terms of power upgrades, but it does fine with simple bolton modifications.

Like any other direct-injected motor, the FA20 is subject to carbon buildup on the intake valves. Eventually this interferes with airflow, causing a drop in power, rough idle, and other unpleasant symptoms. We suggest having that buildup removed using walnut shell media blasting every 30,000 miles or so.

For circuit/track use, the stock brakes are merely adequate. One reason the WRX is inexpensive is that it uses budget-bin sliding calipers front and rear. The front rotors are of a decent size at 12.4 inches in diameter, but the feel is pretty squishy and the stock pads fade quickly under hard track use. At a minimum you’ll want to run more heat-tolerant pads and some good performance brake fluid. Better still, upgrade to the STI Brembo brakes.

The WRX is available with either a six-speed manual or a CVT. The CVT isn’t terrible, but the manual is generally the preferred choice for the enthusiast. It can handle more power, and if it does break, it’s not too expensive to repair or replace. The CVT does fine at stock torque levels, but anecdotally it doesn’t seem to tolerate power upgrades as well as the manual. And if you do have to replace a CVT, it costs north of $6000.

If you’re looking at a used WRX, we suggest starting with an unmodified one if possible. We see plenty of cars with no-brand, low-budget intake systems, mail-order ECU tunes, and other questionable modifications. Often the engines fail prematurely on those cars.

The top-spec WRX models have LED low-beam headlamps that I love. They work well and look fantastic.

WRX vs. STI: The WRX is a great value, starting at $26,995. The STI costs a lot more, starting at $36,095. But depending on how much you want to upgrade the WRX, starting with an STI might be the better choice. The STI Brembo brakes alone cost many thousands of dollars. The STI’s six-speed manual Driver Controlled Center Differential gearbox is legendary for being nearly bulletproof. The STI engine, although it’s been around forever, is powerful and modifications for it are plentiful and widely available. Either way, the platform is great and you can’t go wrong.