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Rear Diffuser Extension

Model 3 Highland Performance
Rear Diffuser Extension
INSTALLATION GUIDE

  • Parts List
  • Tool List
  • Release of liability and product warranty
  • 01 Step 1: Clean Surface
  • 02 Step 2: Test Fit
  • 03 Step 3: Prep Surface
  • 04 Step 4: Installation
Parts List
  • UP Rear Diffuser Extension
  • Adhesive Promoter

Note: IF you plan to install both the UP rear diffuser trim as well as the rear diffuser extension, be sure to install the diffuser extension first prior to installing the rear diffuser cover. The placement of the rear diffuser trim may be affected by the placement of the rear diffuser extension.

Tool List
  • Gloves
  • Rubbing alcohol, or equivalent no-residue cleaning solution
  • Microfiber cloth or equivalent cloth
Release of liability and product warranty

By installing or using this product, you understand and agree with the following: If you do not agree, do not proceed with the installation and return this product within 30 days for a full refund of the purchase price from the company from which you have purchased it.

  • I understand and agree that this product is intended to be installed for use on private roads and in jurisdictions where the use of this product is deemed legal by the local authorities. Furthermore, I understand and agree Unplugged Performance does not have any knowledge or control of regulations in my local jurisdiction, and it is up to me to determine if the product is acceptable for use with my vehicle.
  • I understand that Unplugged Performance has done testing of this product on road and on closed racetracks but does not have the ability to test the vehicle for localized standards and regulations.
  • I understand and agree that if the vehicle manufacturer determines that any Unplugged Performance products have contributed to a problem with the vehicle it may affect the vehicle’s warranty. Furthermore, I understand and agree that Unplugged Performance has no duty nor ability to be involved in internal manufacturer decisions.
  • I understand and agree that if this product is given to an installer for installation on my vehicle, I have read and agreed with all the previous, even if I am not personally installing these parts on my vehicle. Furthermore, I understand and agree that this product should be installed by a trained professional that is familiar with both the vehicle as well as this product. Furthermore, I understand and agree that I and/or my chosen installer will follow the installation instructions carefully and dutifully test the vehicle post-installation in a safe and controlled environment to ensure proper operation.
  • I understand and agree that by installing this product Unplugged Performance and all associated persons and entities as well as the vehicle manufacturer and all associated entities must be held harmless in the event of any suit, damages, or other legal action. Furthermore, I hereby release Unplugged Performance and any associated entities from any and all liability for any potential claim or claims.

If you do not agree with any of the above statements, you should return the product immediately. For more information please see our Terms and Conditions

01 Step 1: Clean Surface

Be sure to prepare the surface that the rear diffuser extension will make contact with prior to install. Be sure to use a cleaning solution that does not leave any residue. If the contact areas are unclear, you can test fit the rear diffuser extension to confirm which areas need to be cleaned.

MODEL 3 PERFORMANCE CARBON AERO KIT INSTALL 00083

02 Step 2: Test Fit

Place the rear diffuser extension over the factory rear fascia to check for proper fitment. The primary goal here is to cover the factory plastic extension without impacting visibility of rear light and reflector indicators.
MODEL 3 PERFORMANCE CARBON AERO KIT INSTALL 00084
Before you install the rear diffuser extension, be sure to pull the backing tape at each edge so that it can be pulled away once the lip spoiler is in the correct location.

03 Step 3: Prep Surface

Once you have determined where to place the rear diffuser extension, apply the supplied adhesive promoter to the areas where the rear diffuser extension adhesive will contact the fascia.

04 Step 4: Installation

Install the rear diffuser extension onto the rear fascia. Adjust the rear diffuser extension accordingly until desired placement is achieved.

MODEL 3 PERFORMANCE CARBON AERO KIT INSTALL 00095
Once desired placement is achieved, apply pressure towards the rear diffuser extension while removing the lead ends to ensure the desired placement is locked in place.

Congratulations! You have completed your rear diffuser extension!

The cure time for the adhesive is a few hours, so be sure not to expose the car to moisture for at least 24 hours after installation. Otherwise, you are all set to go!

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WHAT OUR CUSTOMERS SAY

RATED 4.96 (250 REVIEWS)
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With real reviews from real customers, shop UP products for your Tesla Model S, 3, X, Y and Cybertruck with confidence. Leave reviews and earn up to 2000 UP Rewards points each, redeemable towards exclusive UP Products.

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Vanja K. February 03, 2026
These are exactly what I was expecting. I waited over a year for them. Pandemic backorders and all. It took me about 6 hours to install with help from a friend. The fronts were the worst part. You have to have the spring compressors mounted just right and really compress them a lot to assemble the...
Tim H. January 05, 2023
Love the simple look to this decal
edgar M. November 21, 2025
One of my favorite upgrades to the Model 3, allows for fine-tuning of the entire suspension system to balance the car out. Each notch makes a noticeable difference, so certainly flexibility with the settings. I started with Medium/Medium settings and tuned them according to the car's handling.
Shimmy October 23, 2024
LOVE my new UP-03 wheels. Super light, super strong and they look so good. Super high quality finish on the wheels too, worth every penny. Have had the wheels for just a few days and have gotten tons of compliments on the road and at the track. These are the best wheels you can buy for your Tesla,...
zackfeldstein9 January 10, 2023
This has been one of the best upgrades Ive made to my Plaid. Really makes the car much more stable at high speed, corners better, and there is no loss in comfort even in the stiffest setting.. Very happy with this bar!
Robert M. October 10, 2022
I ordered my satin graphite UP x BBS Flugplatz wheels in March 2022 and got them delivered and installed in June 2022. The wheels were ceramic coated after delivery. I am running 255/35 Falken tires (all-seasons). These wheels have an amazing design and paint finish. They do a great job at exposing...
Kyle R. November 03, 2022
I loved upgrading my front brakes to BFB Carbon, after a few track days and realized I want the rear as well, plus now the aesthetics are on point! (look weird with only the front carbon IMO)
Jorge (. August 23, 2022
Having purchased a UP Sport coilover kit for my Model 3, I purchased this kit for my Model Y as well along with Camber & Toe arms. This kit makes an amazing difference to the ride quality and handling on my Model Y. The car handled surprisingly well on the track with minimal rollover thanks to the...
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Unplugged Performance is the world leader in premium performance upgrades for Tesla vehicles. With our USA-made line of stylish and high-performance parts, our sole focus is on holistic development and improvement of all Tesla cars.
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