Kit at a glance

Vehicle-specific 2018–2023 Ford Mustang S550 facelift widebody kit: plug-and-play fitment without weeks of sanding and cutting.

Fits: 2018, 2019, 2020, 2021, 2022, 2023 Ford Mustang (S550 facelift). GT and EcoBoost: direct fit. Convertible: kit fits, ducktail spoiler excluded (different trunk lid). 2018–2020 Shelby GT350 & non-GT bumpers: different front bumper, test-fit the bumper endings first (no sanding or cutting). Not for 2015–2017 pre-facelift cars (separate 2015–2017 kit).
Material: 3.5 mm automotive-grade ABS plastic — thick enough for durability, light enough to keep weight down. CNC-cut from vehicle-specific 3D scan data. Black in mass, wrap-ready.
Added width: front +3.54 in (90 mm) per side, rear +4.33 in (110 mm) per side.
Parts included: front fender flares (2), rear fender flares (2), side skirts (2), bumper endings, front lip spoiler.
Ducktail spoiler: included only in the “Full kit with ducktail spoiler” configuration; also sold separately as the S550 Ducktail Spoiler.
Mounting hardware: not included, sold separately.
Modifications needed: Direct fit on GT/EcoBoost, no weeks of sanding or cutting. 2018–2020 GT350 and non-GT bumpers: test-fit the bumper endings first, no sanding or cutting.
Installation time: 1–3 days at a body shop, excluding paint/wrap.
Wheels & tires: typically 19x10 wheels with 275–285 mm tires front and 19x11 or 20x11 wheels with 295–315 mm tires rear, depending on offset.
Paint prep: light sanding and primer recommended before paint.
Availability: In stock.
Made in: Bursa, Turkey.

SHIROKAI S550 in the press:

A build on our S550 kit: UK magazine Stance Auto featured Kez Martin's 2016 Mustang GT on the SHIROKAI S550 widebody kit in February 2021. A 2016 car is a pre-facelift model and runs the 2015–2017 version of the kit; this page is the 2018–2023 kit. Read it: Stance Auto: Kez Martin - 2016 Shirokai Mustang GT.

See all SHIROKAI builds in the press

The SHIROKAI 2018–2023 Mustang S550 Widebody Kit is engineered for the facelift Ford Mustang S550 platform, giving GT and EcoBoost builds a wider stance, stronger side profile, and more room for an aggressive wheel and tire setup — while still following the factory body lines.

Fits 2018, 2019, 2020, 2021, 2022, 2023 Mustang GT/EcoBoost (facelift S550).

This is not just an overfender kit. Each SHIROKAI Mustang S550 widebody kit is CNC-cut from platform-specific 3D scan data for cleaner fitment, better proportions, and less fabrication drama during installation. Made from premium automotive ABS plastic, it brings the Kaiju feeling and keeps every line looking intentional.

Ford Mustang S550 (2018-2023) Widebody Kit — Quick Facts

Fits: 2018–2023 Mustang GT and EcoBoost (plug-and-play), Convertible kit-only (spoiler excluded), 2018–2020 Shelby GT350 with a bumper check (test-fit first)
Material: Automotive-grade ABS plastic, 3D-scanned and CNC-cut from OEM body
Width added: +3.54 in (9 cm) per side front, +4.33 in (11 cm) per side rear — 180 mm total at the front and 220 mm total at the rear
Install: 1–3 days at a body shop (excluding paint/wrap), plug-and-play for 2018–2023 GT/EcoBoost with stock bumper
Includes: Front flares, rear flares, side skirts, bumper endings, front lip spoiler; rear ducktail spoiler only with the “Full kit with ducktail spoiler” configuration. Mounting hardware is sold separately
Price: See the current price for your selected configuration above.
Designed for: Post-facelift S550 with redesigned hood, headlights, and front bumper geometry
Shipping: Worldwide delivery. Shipping is calculated for your address in your selected currency at checkout.

What’s in the Ford Mustang S550 Widebody Kit

Front fender flares
Rear fender flares
Side skirts
Bumper fender endings
Front lip spoiler
Rear trunk spoiler — only with the “Full kit with ducktail spoiler” configuration
Mounting hardware is sold separately

Not your year? 2015–2017 vs 2018–2023 — how to tell

2015–2017 (pre-facelift): sharp three-piece LED headlights with the vertical “gills”, flat hood with no vents, taller front bumper opening. 2018–2023 (facelift): slimmer lower-set headlights with tri-bar LED DRLs, hood with twin heat extractor vents, lower and wider bumper grille.

Have a 2015, 2016 or 2017 Mustang? See the 2015–2017 S550 widebody kit →

Looking for build ideas? See real cars in our widebody Mustang S550 gallery.

Width & Specs

Front fenders add 3.54 in (9 cm) per side, rear fenders add 4.33 in (11 cm) per side, measured from the stock arch — run wider wheels and tires for more grip on road and track.

High-grade automotive ABS plastic
Black in mass — wrappable straight out of the box (light sanding + primer recommended for best paint result)
Vehicle-specific panels; professional test fitting and installation recommended

Ford Mustang S550 Widebody Kit Fitment Guide (2018–2023)

Confirmed fitment for 2018, 2019, 2020, 2021, 2022 and 2023 Ford Mustang:

Year	Model	Fitment	Notes
2018–2023	Mustang GT	✅ Direct fit	Vehicle-specific fit; test fitting and drilling are required
2018–2023	Mustang EcoBoost	✅ Direct fit	Vehicle-specific fit; test fitting and drilling are required
2018–2023	Mustang Convertible	⚠️ Partial fit	Kit fits, ducktail spoiler excluded (different trunk lid)
2018–2020	Shelby GT350 & non-GT bumpers	🔧 Bumper check	Different front bumper: test-fit bumper endings first, no sanding or cutting
2015–2017	Mustang S550 pre-facelift	❌ Different kit	See the S550 2015–2017 kit →
2005–2014	Mustang S197	❌ Different kit	See the S197 widebody kit →

Not sure about your trim? Email i@shirok.ai — we confirm fitment within 24h.

Why S550 Owners Love It

All you need is steady hands and a heat gun — the kit is plug-and-play on GT/EcoBoost, with no weeks of sanding or cutting. With a growing community of SHIROKAI Mustang owners, this S550 kit became an absolute best seller and delivered strong results. If there’s a Mustang with a SHIROKAI kit at a show, it gets attention and love. Fitment is one of the biggest strengths of this wide body S550 setup — SHIROKAI is known for parts that fit straight out of the box, so you spend less time in the shop and more time driving. Whether you search for a mustang widebody, a mustang wide body build, or an S550 body kit, this keeps clean bodylines with a bold, planted look.

Wheels & Tires

Dial in your exact setup with our Widebody Wheel Fitment Calculator.

Finishing

Want to test our quality first? The ducktail spoiler is included in the full kit, and also sold separately — same ABS material, same fitment standard, fits 2015–2022 S550 trunk lids. See the S550 Ducktail Spoiler →

Technical Specifications

Spec	Detail
Material	Automotive-grade ABS plastic
Manufacturing	CNC-cut from OEM 3D scan data
Front flare width	+3.54 in / +9 cm per side
Rear flare width	+4.33 in / +11 cm per side
Total added width	180 mm total at the front; 220 mm total at the rear
Components	Kit components: front flares (2), rear flares (2), side skirts (2), bumper endings, front lip spoiler; ducktail spoiler only in the full-kit configuration
Mounting	Plug-and-play fitment on GT/EcoBoost — no weeks of sanding or cutting. Rivnut mounting; mounting hardware not included (sold separately)
Install time	1–3 days at a body shop, excluding paint/wrap
Paint prep	Light sanding + primer recommended for best finish
Wrap compatibility	Yes, surface ready out of the box
Compatible vehicles	2018–2023 Mustang GT/EcoBoost (plug-and-play), Convertible (kit-only), 2018–2020 GT350 (bumper check)
Body generation	S550 facelift (post-2018 redesigned front fascia)
Country of manufacture	Turkey (Bursa)
Support	Lifetime tech support from manufacturer

For best results, professional installation is recommended. The finish wraps from the box (light sanding + primer for paint). Every Ford Mustang S550 widebody kit is built for style, function, and quality — the bold flares and precise fit take your Mustang to the next level.

Frequently Asked Questions

Will this kit work on my Mustang Convertible?

Partially. The flares, side skirts, lip, and bumper endings all fit a 2018–2023 Convertible identically to the Coupe. However, the ducktail spoiler is excluded — Convertibles use a different trunk lid geometry that the spoiler doesn't match. Convertible owners typically order the kit without the ducktail spoiler option at checkout.

What about Shelby GT350 fitment?

The GT350 (produced 2018–2020) uses a different front bumper than the standard GT, so we recommend a quick test fit of the bumper endings before install. No sanding or cutting of the flares, skirts or spoiler; all other panels fit identically to the GT. Note: GT350 production ended in 2020 — for 2020+ Mustangs above the GT, the GT500 uses a substantially different front-end and is not covered by this kit.

Is this kit different from the 2015–2017 S550 kit?

Yes. The 2018 facelift Mustang received a redesigned hood, headlights, and front fascia — so the kit requires a different front-section design. The actual flare and skirt dimensions are identical between the two S550 kits (180 mm total front width and 220 mm total rear width), but the bumper endings and front lip are platform-specific. If you have a 2015–2017, see our S550 2015–2017 widebody kit.

How does the width compare to other SHIROKAI Mustang kits?

This S550 kit adds 180 mm of total width at the front and 220 mm at the rear (9 cm front and 11 cm rear per side). Our S197 kits add 180 mm total at the front and 240 mm at the rear (9 cm front and 12 cm rear per side). The slightly narrower S550 stance is intentional — it follows the S550's tighter factory body lines for a cleaner, OEM+ aggressive look rather than maximum-width drama. Both generations share the same 9 cm front-fender addition.

How long does installation take?

Typical body shop install takes 1–3 days (excluding paint/wrap), including test fit, drilling, and rivnut setup. The install requires drilling holes in the fender for rivnut-mounted flares — this is standard procedure for properly secured aftermarket widebody and shouldn't be attempted without the right tools.

Will my doors still open with the flares installed?

Yes. The flares follow the factory door cutline. Both doors remain fully operable at any opening angle. The kit does not interfere with door handles, mirrors, or fuel filler door operation.

What wheel and tire setup works with this kit?

The added width supports significantly wider wheel and tire setups than stock — typically 19x11 or 20x11 wheels with 295–315 mm tires in the rear, and 19x10 with 275–285 mm tires up front depending on offset preference. Use our Widebody Wheel Fitment Calculator for precise sizing tailored to this kit.

QTP 4in Weld-On QTEC 3 Bolt Flange