SKU: 55452161434

Flow Designs GT Mustang S550 FM Flow-Lock Rear Diffuser

Sale price$171.00 Regular price$190.00
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Ships within 48 hours · Estimated delivery Jul 30 - Aug 4

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Description

Flow Designs GT Mustang S550 FM Flow-Lock Rear DiffuserSuits 2015 2017 Ford Mustang GT S550 FM INSTALL DOES NOT REQUIRE REAR BUMPER REMOVAL Details Experience Flow Lock rear diffuser for your Mustang S550 FM, sharing the same durability and technology as our renowned WRX, Golf GTI & MK3 Focus RS line up which is trusted by car enthusiasts worldwide. The rear valance and diffuser fins will clear the Mustang S550 FM dual exhaust tips with ease, and rear bumper removal is not necessary for installation of

Suits 2015-2017 Ford Mustang GT S550 FM

INSTALL DOES NOT REQUIRE REAR BUMPER REMOVAL



Details

Experience Flow-Lock rear diffuser for your Mustang S550 FM, sharing the same durability and technology as our renowned WRX, Golf GTI & MK3 Focus RS line up which is trusted by car enthusiasts worldwide. The rear valance and diffuser fins will clear the Mustang S550 FM dual exhaust tips with ease, and rear bumper removal is not necessary for installation of the diffuser. 10 year warranty applies for the rear valance (excludes ABS fins).

The Flow-Lock interlocking system allows for the final assembly of the diffuser fins without tools or fasteners. A simple push and click and the kit is assembled and ready for installation - this means zero exposed hardware giving you the cleanest look for your Mustang S550 FM rear. Front lip splitter is also available for the Mustang S550 FM.

No more L-brackets, no additional exposed hardware and no double-sided tape, experience the Flow-Lock difference today!
 

Valance is installed to the car through bolts and nuts while the Flow-Lock diffuser fins simply click into the valance (once locked into the valance it is secure). It is also possible to install when your car is on the ground.


GT Mustang S550 FM Rear Diffuser Kit Includes:

  • Mustang S550 FM rear diffuser (rear valance and Flow-Lock diffuser fins)
  • 2 Flow Designs stickers
  • Fitting kit

GT Mustang S550 FM Rear Diffuser Material & Finish:

  • Valance: 10mm thick polyethylene composite, bevelled edges
  • Flow-Lock diffuser fins: 4.5mm thick textured ABS 
  • Valance: Finish available in gloss black, or scratch-resistant textured matte black
  • Flow-Lock diffuser fins: scratch resistant textured ABS plastic
  • CNC engraved logo and features

Others Who Own This Kit:

Tell me about ABS plastic!

Please note that although all our precision-made ABS accessories are extremely strong and durable, they do not hold the same shatterproof label as our 10mm thick polyethylene composite splitters. The accessories are manufactured in ABS with the intention that they will be lighter, bolt-on attachments that will improve aesthetics and are easily replaceable if they become damaged from varying road conditions. 

Install Instructions (PDF)

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 55452161434

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4.2 ★★★★★
Based on 23 reviews
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Verified Purchase
Jesse Slater
Grantham, US
★★★★★ 3
Good enough
Size: 15x6.8, Color: Black
As cheap as the day is long but functional. These are basically made out of highly compressed paper and finished to feel like wood. The first one I put up was good with a little tilt to the back which is fine. The second one has a more severe tilt and I had to bend the bracket down to decently level it out. They are sturdy enough to hold quite a bit of weight and look good for what they are. I'm not impressed but I'm also not disappointed, the price is a bit steep for what they are but they serve their purpose.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on November 15, 2025
S
Verified Purchase
Satz
Grantham, US
★★★★★ 4
Great, but bring your own inserts.
Size: 24x7.9, Color: Black
These work great, easy to install. Happy with them. Only problem was the instructions say don’t use the include inserts on wallboard, which meant I had to go out and purchase my own. That’s OK, because I like to use inserts I trust.
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Reviewed in the United States on December 9, 2025
L
Verified Purchase
Linda Gill
Lake Worth, US
★★★★★ 5
Sturdy and attractive
Size: 15x6.8, Color: Black, Size: 15x6.8, Color: Black
Love the shelves, great quality and design. They are very sturdy and perfect for my need. I ordered wine glass holders from Amazon and attached them to the shelves. Impressed and amazed at the look.
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Reviewed in the United States on November 18, 2025
P
Verified Purchase
Placeholder
Waukegan, US
★★★★★ 5
Beautiful shelves.
Size: 24x7.9, Color: White
Beautiful shelves. Easy to put up once you get the holes level.
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Reviewed in the United States on April 28, 2026
S
Verified Purchase
Sonya H
Phoenix, US
★★★★★ 5
Excellent floating shelves look very high end
Easy to install and bracket is hidden once shelf is installed Very sturdy. Wipe clean surface.
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Reviewed in the United States on April 21, 2026

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