Subaru remapping

EJ257, WRX STI

The EJ257 is Subaru's 2.5-litre turbocharged flat-four, the engine behind the WRX STI right through to the UK Final Edition, which produced up to 300 bhp from the factory. It is the engine most closely tied to Subaru's rally heritage, running through the Symmetrical AWD system that has always been central to the STI's identity rather than an option bolted on afterwards.

FA20, earlier EU-market WRX

The FA20 is a 2.0-litre turbocharged flat-four fitted to earlier EU-market WRX models, producing 268 bhp from the factory, also through Symmetrical AWD. It is a different engine family to the EJ257 despite the shared WRX badge, and the two should never be treated as interchangeable remap projects.

FA24, current WRX and Levorg

The current WRX is not sold new by Subaru UK; the US-spec-derived FA24 turbo cars seen on UK roads come in through specialist importers. The current-generation Levorg is officially sold new in the UK, but runs a different, smaller turbocharged unit, Subaru's 1.8-litre CB18 flat-four, not the FA24. The naturally aspirated FA24 found in the BRZ and GR86 is a different engine again, and the WRX's turbocharged FA24 carries genuinely different remap headroom as a result.

FA24, naturally aspirated BRZ

The BRZ runs the same FA24 architecture without forced induction, producing 231 bhp. There is no boost to open up here, so a remap on this engine refines timing and fuelling for sharper response rather than chasing a large power figure, an honest ceiling rather than a shortfall. The BRZ shares this engine with the Toyota GR86, built jointly by the two manufacturers, covered on our Toyota hub.

Stage 1 calibration at Manchester Dyno Centre is developed and verified on the 4WD Bapro dynamometer, checked against your specific car's own baseline pull. See the full breakdown on our dedicated BRZ and Levorg pages, with WRX and WRX STI pages following at /vehicles/subaru/wrx/ and /vehicles/subaru/wrx-sti/.

Stage 1 is available on the turbocharged EJ257, FA20 and FA24-turbo platforms, developed and verified on our 4WD Bapro dyno. Stage 2 is available where supporting hardware is fitted, and we will advise honestly on whether your specific car's setup justifies it. A standalone rolling road session, without any remap attached, is a genuinely useful option across the range, whether that means a documented figure before committing to a remap or a post-modification check. Economy remapping is worth a conversation for Levorg owners covering high motorway mileage. We do not offer a Stage 2 programme on the naturally aspirated FA24 in the BRZ, there is no supporting hardware pathway on that engine that would justify one.