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The CMST "Streamline" carbon-fibre widebody kit for the 2025 Tesla Model Y (the "Juniper" facelift) is a comprehensive bolt-on, tape-on and bracket-mounted upgrade that fits the latest Model Y without altering the chassis. The Streamline ("流光") kit goes beyond a lip-and-skirt set: it adds wider front and rear arches, a deep front lip, side skirts, a rear diffuser and a raised carbon spoiler, all in pre-preg dry carbon fibre. Because of the widebody arches, this is a more involved fit than a small kit and is best handled by an experienced installer with a hoist.

This guide walks through the Streamline kit in the order we recommend, with the alignment, clearance and tyre-cover cautions that matter on a widebody Model Y.

Quick facts

• Vehicle: Tesla Model Y (2025 "Juniper" facelift)
• Fitment years: 2025-onward
• Kit: CMST Streamline ("流光") carbon-fibre widebody
• Key pieces: front lip, widebody front and rear arches, side skirts, rear diffuser, raised spoiler
• Material: dry carbon fibre, gloss or matte clear-coat
• Fixing method: 3M VHB tape + structural adhesive + self-tapping screws + arch brackets (no chassis cutting)
• Skill level: advanced; two people and a hoist recommended
• Estimated time: 6–9 hours

Tools and preparation

A widebody kit rewards a careful dry-fit. Offer every panel up before any tape comes off, mark the positions with masking tape, and confirm the arches clear the tyres at full lock and full suspension travel. You will need:

• Trim-removal and plastic pry tools
• Electric screwdriver or impact driver, plus a drill for arch pilot holes
• Adhesion promoter and clean microfibre cloths
• Fine sandpaper (240–400 grit) to key the bonding faces
• 3M VHB tape (usually pre-applied), structural adhesive and the supplied arch brackets
• Masking tape for alignment, and a heat gun for cold-weather tack
• A hoist, which is close to essential for the arches, skirts and diffuser

Handle the carbon by its edges on a padded surface; the clear-coat marks easily. Bond at room temperature — 3M acrylic tape grabs best between roughly 21°C and 38°C — and warm the panels if the workshop is cold.

Step 1 — Front lip

Offer the front lip up to the lower bumper to check the clip positions before committing adhesive. Clean the bumper face with the adhesion promoter, sand the lip's inner upper edge, and run 3M tape with a few dabs of structural adhesive. Peel one end of the backing, locate the lip with a helper steadying the far side, confirm it sits centred, then peel the rest and press home. Drive self-tapping screws into the lower edge to lock it, and bond the corner sections last.

Step 2 — Widebody front and rear arches

The arches are the defining pieces and the most demanding to fit. Dry-fit each arch over the standard guard and mark where it overlaps. Key the bonding faces, clean them with the promoter, and apply 3M tape with structural adhesive along the contact line. Where the kit supplies brackets, fit them to the inner guard so the arch is mechanically supported rather than relying on tape alone — pre-drill the pilot holes the brackets call for. Locate each arch, confirm the gap to the door and bumper is even, then press the tape home and secure the brackets. Check tyre clearance at full steering lock and compress the suspension to confirm the tyre cannot foul the arch lip; a widebody is only an improvement if the wheel-and-tyre package fits inside it.

Step 3 — Side skirts

With the arches set, the skirts bridge them along the rocker. Clean and sand the rocker line, run 3M tape along the skirt's top inner edge with a few points of adhesive, and clean the matching rocker area. Peel one end, lift the skirt into place with a helper, and check it meets both arches cleanly and follows the sill. Confirm the position, peel the rest and press home, then fix the underside with self-tapping screws, adding an extra screw at the leading edge.

Step 4 — Rear diffuser

Remove the rear arch fasteners and the lower bumper trim so the diffuser can seat flush, and support the number-plate light on its bracket. Offer the diffuser to the rear under-tray, line up the fins so they sit level, and fix the centre with structural adhesive and the outer points with self-tapping screws. Route and reconnect any rear lighting through the diffuser channel, observing the marked positive and negative leads, then refit the bumper trims and arch liners.

Step 5 — Raised carbon spoiler

The raised spoiler lifts the trailing edge of the roofline and is the most eye-catching piece. Sand and clean its bonding feet, apply 3M tape with a few dabs of adhesive, and clean the boot-lid contact points with the promoter. With a helper holding one side, peel one end of the backing, align the spoiler centrally to the boot lip, confirm it is square, then peel the rest and press each foot home. Hold it under pressure so the tape grabs.

Fitment tips and cautions

• Confirm tyre clearance before you commit. A widebody must clear the tyre at full lock and full bump; check this during the dry-fit, not after.
• Use the brackets. Tape alone is not enough for the arches — fit the supplied brackets so they are mechanically held.
• Mind the lowered overhang. The deep lip and diffuser reduce front and rear clearance, so take steep entries and speed humps slowly and at an angle.
• Bond warm. Warm the panels and the car with a heat gun if you are working below about 18°C.
• Paint-match if you want body colour. The carbon ships clear-coated; a panel shop can respray the arches and skirts to match before fitting.

FAQ

What does "Streamline" (流光) mean for this kit?

"Streamline" is CMST's name for this widebody design for the Juniper Model Y. It signals the flowing arch-and-skirt treatment that widens the stance, as opposed to a restrained lip-only kit.

Is the Streamline kit a true widebody?

Yes. It adds wider front and rear arches over the standard guards, which is why it needs brackets and a tyre-clearance check rather than fitting with tape alone. It changes the car's track appearance, not just its lower trim.

Will it fit the older pre-2025 Model Y?

No. The Streamline kit is cut for the 2025 Juniper facelift, with its revised bumpers and body lines. The earlier 2021–2024 Model Y uses a different kit, so confirm your model year before ordering.

Do I need new wheels or spacers for the widebody arches?

Not necessarily, but the arches give room for a wider or more deeply offset wheel-and-tyre package, and that is usually the point of fitting them. Check your chosen wheel offset and tyre width against the arch during the dry-fit so the tyre sits correctly inside the new guard.

Can I fit this at home, or should it be professionally installed?

The lip, skirts, diffuser and spoiler are within reach of a skilled DIY installer, but the widebody arches demand careful bracketing, alignment and clearance checking. Most owners have the Streamline kit professionally fitted to get the arches and paint-match right.

Professional fitment in Australia

A widebody kit is worth fitting properly. AME Motorsport stocks the range and can arrange installation and paint-matching. Explore the CMST body kit range for Tesla, view the CMST widebody fenders for Tesla and matching CMST diffuser for Tesla, or start with the full CMST body kit collection for advice on the Streamline package for your Model Y.