Find a trail through the archive.

Subaru/STI has fielded WRX STI "NBR Challenge" cars (livery/entrant number 106) in the actual Nurburgring 24 Hours endurance race across multiple years — a different program from the Type RA NBR Special outright-lap-record car above and should not be conflated with it: one is a time-attack record car, the other a multi-year endurance-racing entry. Specific NBR Challenge race results/class finishes by year are not yet researched.

A Prodrive-built WRX STI Type RA NBR Special, driven by Richie Stanaway (age 25 at the time per the reporting), set a 6:57.5 lap of the 12.8-mile/20.6km Nordschleife — reported as a new record for a four-door sedan, beating a prior 7:32 mark set by an Alfa Romeo Giulia Quadrifoglio. The car used a full roll cage, a WRC-derived 2.0L boxer engine tuned to 600+ hp at 25 psi boost and 8,500rpm, a sequential gearbox with automatic clutch, and an F1-style drag-reduction aero system generating up to 650lb of downforce; it reportedly also set records at the Isle of Man TT course and 3rd fastest overall at the Goodwood Festival of Speed hillclimb. The exact year of the Nurburgring run itself is not pinned down in the source material used — the press material referenced is undated, and this remains an open research thread.

Know the decade-plus JDM-vs-US gap before shopping for a WRX or STI

Use NASIOC and IWSTI build threads as a maintenance reference — cross-check before you trust them

Subaru's first world car, and STI's first prepared car.

Turbo comes back to the US Legacy — borrowed straight from the WRX STI.

The EJ20 is the signature engine of the WRX/STI lineage and the reason Japan and the US ran different WRX/STI displacements for most of the model's history: Japan's road-tax bands and an informal manufacturers' horsepower cap kept JDM cars on the 2.0L EJ20 family all the way to the 2017/2018 S208, the final catalog JDM STI built on it, while the US ran the larger 2.5L EJ25 family from the WRX STI's 2004 introduction. The EJ20's turbo variants powered every Group A/N WRC-homologated Impreza and JDM STI special edition from the 1994 Version 1 onward.

The EJ25 was the mainstream 2.5L engine across US-market Legacy, Outback, Forester, and Impreza applications, and became the US WRX STI's engine from 2004 onward in EJ257 turbo form. Aftermarket-service-industry sources (not a manufacturer statement or independent engineering study) describe two distinct head-gasket failure patterns: internal coolant leaks on 1996–1999 first-generation EJ25D engines, and external leaks around the 100,000-mile mark on later EJ251/EJ252/EJ253 variants — a pattern those same sources say improved with post-2012 revisions and the FA/FB-family replacement, though this remains a service-blog-level claim rather than a rigorously verified one.

The FA20 is the shared engine at the center of the Subaru-Toyota BRZ/86 joint-development program — Subaru supplied the core engine design (on its own Impreza-derived chassis), and Toyota added its D-4S injection system, with the resulting unit carrying two names for one physical engine: FA20 (Subaru) and 4U-GSE (Toyota). Its 86mm-by-86mm bore and stroke is the literal source of the 86 nameplate. A separate turbocharged branch, FA20F/FA20DIT, became Subaru's mainstream direct-injection turbo four across the Legacy GT, Forester XT, and WRX.

The FA24 headlines the Ascent, Subaru's modern three-row, and represents a deliberate departure from the larger flat-six engines (the SVX's EG33, the Tribeca's own H6 units) Subaru had previously reached for in flagship or large-vehicle applications — pairing turbocharging with Subaru's more typical four-cylinder boxer displacement instead. A naturally aspirated FA24D variant separately powers the second-generation BRZ and Toyota's GR86.

Track your 2013 BRZ's valve-spring recall history, and watch the engine closely afterward

Confirm the 2013 BRZ's valve-spring recall (NHTSA 18V-772 / WTY-84) was completed — and ask where

The generation the US never got the turbo version of.

Ask for head-gasket service history on a 1998–2004 non-turbo Impreza (including the 2.5RS)

The generation where the WRX and STI finally reached the US.

The generation where WRX/STI stopped being an Impreza trim.

Approximately 1,000 units — UK-only, built by Prodrive specifically to counter grey-market JDM Impreza imports

125 units reported (90 sedans + 35 wagons) — one other source claims 135; unresolved

Subaru's rally-homologated performance icon, built to satisfy World Rally Championship Group A/N rules, and the single family with the deepest JDM-vs-US divergence in the whole marque — from the WRX/STI US introduction gap to a long list of JDM-only limited editions like the 22B.

Self-described as the largest Subaru STI-specific forum in the world, explicitly scoped to WRX/STI rather than the full lineup. Structured around member build/modification journals, how-to installation threads, a news/rumors section, and a classifieds section — visibly active as of this research pass.

The largest and most established Subaru performance-enthusiast community found in this project's research, covering performance information across nearly the whole Subaru lineup (Impreza, WRX, STI, Legacy, Forester, Tribeca, Baja, SVX) despite its Impreza-focused name. Per its own wiki, founded April 1999 by Alex Shikhmuradov and Robert Eldridge-Waks and formally organized 28 July 1999 — those founder/date specifics come from search-result synthesis of the club's own wiki, not yet independently re-verified, so treat them as provisional.

A WRX kid at a parking-lot meet and a Forester owner at a trailhead might not agree on a single thing — except that their engines lie flat and their all-wheel drive runs straight down the middle. Subaru didn't invent either idea. It just built an entire identity, and nearly its whole lineup, on the two of them together.

Won the 2001 drivers' championship with co-driver Robert Reid, driving the Impreza WRC2001 — the first four-door World Rally Car Impreza, based on the GD-chassis WRX. Also competed for Subaru in the 1999-2000 seasons per the team-history source.

The turbo XT arrives, and a JDM-only Forester STi that never crossed the Pacific.

Know which engine your SG-generation Forester actually has before servicing it

DCCD is an STI-specific, manual-only system — don't assume a WRX has it

The Outback's first factory turbo, and its first six-cylinder as a range-topper.

The chassis where the US got its own S-series STI for the first time ever.