The Bilstein B8 Performance Plus front left strut assembly (MPN 35-249498) is a monotube damper unit for the driver-side front corner of Subaru WRX and WRX STI models. Owners on user forums describe the B8 as a Bilstein option meant to pair with aftermarket lowering springs rather than factory ride height, which is the niche this strut targets. Because it ships as a complete strut assembly, it replaces the whole front unit instead of just the cartridge.
Factory struts are often the weak link once a Subaru is lowered. One forum poster notes that dampers are only at their prime for roughly 30 to 40k miles on OEM springs, and increasing the spring rate makes performance degrade faster. Replacing the front left strut alongside a lowering spring keeps damping matched to the new rate. Buyers running a matched setup will usually want the front right unit (MPN 35-300083) as well. Fitment needs checking before you buy. Listings disagree on model years: the product name reads 2015-2017, while other fitment tables run through 2020 or 2021. Confirm against your VIN, and confirm with the manufacturer if the year range matters.
Details vary. Some product listings say the strut is intended only for lowering springs, while a user forum discussion argues that spring rate matching matters more than brand. Confirm with the manufacturer before fitting it to stock springs.
Yes. User forums advise getting a wheel alignment after a lowering-spring install, and the same applies when a new front strut changes geometry.
User forums report that many owners fit shorter, firmer bump stops with lowering springs so the suspension does not ride on them and bottom out over bumps.
A user forum install guide written for the 2008-2014 WRX notes that the same process applies to most Subarus because the chassis is similar. Break the lug nuts loose while the car is on the ground, then raise the car and remove the wheel. Disconnect the brake line and ABS sensor bolts from the strut, and mark the camber bolt with a paint pen before removing it so it can go back in the same position. Loosen the nuts at the steering knuckle rather than the bolt heads, then remove the upper nuts from the shock tower. Plan on an alignment once the job is done.
