What we researched for this specific generation: where an enclosure actually fits, what the factory speakers are, how the factory audio is wired, and which real builds and commercial products exist for it. Confidence badges say how well each figure is sourced — this is research, not manufacturer spec.
Body styles covered: 4-Door Sedan
These are researched envelopes, not a guarantee. Measure your own vehicle — the numbers here tell you what to expect, not what you have.
| Location | trunk, stealth/low-profile custom builds preferred by this community |
|---|---|
| Outer bounding box | 9.125" mounting depth (dual-10" product proxy) |
| Known obstructions | Community strongly favors builds designed to take as little trunk room as possible |
| Usable volume estimate | 1.6 ft³ |
Suggested configurations for this vehicle, not prescriptions. Run the numbers in the Box Builder before you buy anything.
| Subwoofers | OEM Kicker factory upgrade kit |
|---|---|
| Box type | sealed |
| Location | factory-designed location |
| Subwoofers | 2x10" sealed, 1.6 ft3, stealth fiberglass build |
|---|---|
| Box type | sealed |
| Location | trunk, low-profile custom |
Sizes and depths below are what research turned up for this generation. Confirm against your own vehicle before cutting or ordering — trim levels vary.
| Factory speaker size | unconfirmed — Crutchfield fit-database coverage confirmed to exist but specific dimensions not surfaced |
|---|---|
| Adapter bracket needed | unconfirmed |
| Tweeter | Dash-corner (front dash, not A-pillar) — real, confirmed 22mm element. Genuinely tight factory location: direct-fit with no cutting or rewiring for a same-size replacement, but larger aftermarket tweeters are a very tight fit requiring modification. Access: pry the grille (4 clips), remove 2 Phillips screws. |
| Factory speaker size | unconfirmed |
|---|---|
| Adapter bracket needed | unconfirmed |
| Tweeter | n/a — tweeter is dash-corner mounted, front only |
| Factory amp / premium audio | Real, specific, split correctly by nameplate within this combined entry. WRX/STI (2015-2021): Harman Kardon confirmed Limited-trim EXCLUSIVE — explicitly NOT offered on base or Premium models, a real, clean negative on the other trims, not just an unconfirmed gap. Impreza: Harman Kardon confirmed on BOTH Sport and Limited trims — a real, wider gate than WRX/STI gets, worth keeping the two nameplates distinct rather than assuming identical trim gating just because they share this entry. |
|---|---|
| Adding subs without a head-unit swap | Confirmed straightforward — trunk-based builds don't touch the head unit. A genuine FACTORY-BRANDED upgrade path also exists: Subaru sells an OEM Kicker subwoofer upgrade kit specifically for 2012-2021 WRX/STI — a real manufacturer-endorsed aftermarket option, not just third-party. |
| Head unit | No replacement needed |
Real rally/tuner enthusiast culture — multiple custom fiberglass 'stealth' box makers specifically for this chassis. Real spec: dual 10", 1.6 ft3 airspace, 9.125" mounting depth. A 12" build at just over 1 ft3 can handle 300W RMS with 5-7 layers of fiberglass construction. Community favors builds designed to take as little trunk room as possible, JL Audio subs (10W3v3, 12W3v3, even a 12W6) are the commonly recommended fit.
Outside links. Some are commercial products, some are owner builds posted on forums — the label says which. We do not endorse any of them.
Each link opens the tool with this vehicle already selected.
Measure your own vehicle. Trim levels, factory subwoofer options, and mid-generation changes all move these numbers, and a box cut to a researched figure that does not match your truck is wasted wood. Where a badge reads Unconfirmed, treat the value as a starting point for your own measurement, not as an answer.