Rear Bumpers

Fits
Porsche 981 Cayman GT4
Rear diffusers are extremely efficient downforce producing devices when designed properly. We set out to produce a functional rear diffuser for the Porsche 981 GT4 using state of the art R&D processes. The assembly blends function and form utilizing carbon fiber, sheet metal, and hard rubber.
Utilizing scan data, CAD, and ANSYS Fluent analysis software; we were able to design and produce a functional and aesthetically pleasing rear diffuser for this Porsche chassis.
The three main diffuser planes are produced from 2x2 twill, autoclave cured, carbon fiber; while the strakes are manufactured from durable polyurethane for longevity.
The entire unit bolts to chassis locations through multiple sheet metal brackets. There is absolutely no drilling or fabrication required for installing this rear diffuser.
*Outside stakes require slight trimming if installing with OEM GT4 muffler*
Kit Includes
• Diffuser Main Plane x 3 (Left, Right and Centre)
• Bracket (4)
• Strake, Hard Rubber (4)
• Stainless Steel Hardware Kit, Includes All Hardware Necessary for Install
- Porsche Cayman GT4 3.8L 2015-16
Fits
Porsche 981 Cayman GT4
Finishing what Porsche started, these fill the void in the 981's underbody. The middle of the vehicle creates drag on automobiles and covering the turbulent areas with flat sheet aluminum reduces this significantly. By improving the airflow to the rear diffuser; the diffuser is able to function better as well.
Produced from sheet aluminum and powder-coated a durable black, they look great and function as intended. Pair this with our rear diffuser to reduce lift and drag simultaneously.
Through CFD, we have estimated the underbody panels reduce the coefficient of drag (cD) by 0.007; or 7 points.
* Will work with other Porsche 981 models, but does take slight modification to mount.*
Kit Includes
• Flat Underbody Pane x 2 (Left and Right)
• Bracket (2)
• Hardware Kit, Includes All Hardware Necessary for Install
Features
Reduce Drag
Increase Fuel Mileage
Improved Diffuser Function
Flat Underbody
Simple to Install
CNC Cut 5052 Aluminum
Powder coated Black for Durability
Produced in the USA
Stainless Steel Hardware Throughout
Rivet-Nut Install Tool Included
- Porsche Cayman GT4 3.8L 2015-16

Fits:
Porsche 981 Cayman GT4 2016
Upgrade the 981 Cayman GT4 style by replacing the oem plastic parts with more performing and eye catching carbon fiber parts with exposed carbon weave. Great Solution as a replacement and to lightweight your GT4.
Manufactured in carbon fiber prepreg autoclave molded at high temperature & pressure with twill 2×2 200 gr. fabric and final lacquering clearcote gloss 90.
Please note: This is a special-order item manufactured to order. In some cases, please allow 4 - 5 weeks for the delivery. Special order items cannot be cancelled from this supplier once your order has been placed.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
SFC981505511
The product you are viewing cross references to these numbers
- Porsche Cayman GT4 3.8L 2015-16
This is a top quality aftermarket part.
Fits:
Porsche 981C Cayman 2014-16
Porsche 981 Boxster 2013-16
Click 'Zoom in' for large parts diagram.
Diagram ref no 3, 4, 5 and 6
This diffuser is not suitable to accept parking sensors. We recommend relocating the sensors into rear bumper. (Drilling required.)
Please note: Delivery time is normally 6-8 weeks.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
98150585380
The product you are viewing cross references to these numbers
- Porsche Boxster 981 2.7L 2012-16
- Porsche Boxster 981 S / GTS 3.4L 2012-16
- Porsche Cayman 2.7L 981 2013-16
- Porsche Cayman S / GTS 3.4L 981 2013-16
- Porsche Cayman GT4 3.8L 2015-16
This is a top quality aftermarket part.
Fits:
Porsche Boxster 981 2.7L 2012-16
Porsche Boxster S 981 3.4L 2012-16
Porsche Boxster Spyder 3.8L 2016
Porsche Cayman 2.7L 981 2013-16
Porsche Cayman S 3.4L 981 2013-16
Porsche Cayman GT4 3.8L 2015-16
Please note: if not in stock, Delivery time is normally 6-8 weeks.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
981898307A
The product you are viewing cross references to these numbers
- Porsche Boxster 981 2.7L 2012-16
- Porsche Boxster 981 S / GTS 3.4L 2012-16
- Porsche Boxster 981 Spyder 3.8L 2016
- Porsche Cayman 2.7L 981 2013-16
- Porsche Cayman S / GTS 3.4L 981 2013-16
- Porsche Cayman GT4 3.8L 2015-16
Porsche Rear Bumpers
At Design911, we supply a wide range of rear bumpers for Porsche models, helping you maintain, personalise and enjoy your car.
Why do Porsche Rear Bumpers matter?
Rear bumpers affect how the back of your Porsche looks and how it copes with everyday knocks. Over time they can suffer from impacts, scuffs, UV fading or cracking, or simply start to look tired compared with the rest of the car. Replacing tired or damaged bumpers helps your Porsche feel better cared for and can prevent small niggles turning into larger jobs later on.
- Keep your Porsche looking smart rather than tired or neglected
- Help protect the rear bodywork from minor impacts and corrosion
- Reduce niggles such as misalignment, rattles or mismatched paint
- Support long-term enjoyment, pride of ownership and potential resale value
Common options & kits
Individual replacement parts
Specific items to address a particular area or issue without changing everything at once.
- Ideal for targeted repairs after scratches, dents or cracks
- Lets you replace only what is needed (skin, carrier, trims, brackets)
- Helps keep initial repair costs under control
Matched sets or pairs
Components supplied together so both sides or related items are renewed at the same time.
- Consistent fit, finish and panel gaps across the rear end
- Helps avoid uneven wear, colour mismatch or ageing
- A sensible choice when refreshing the full rear bumper area
Complete kits
Grouped parts designed to refresh a whole system or area in one go, useful for upgrades and restorations.
- Everything specified in a single package for a given Porsche model or conversion
- Saves time compared with sourcing bumper, supports and trims individually
- Ideal when upgrading to sport, GT or widebody styles, or during restoration
Brands & quality options
At Design911, we stock genuine Porsche parts where available, plus OEM-equivalent and carefully selected aftermarket brands. This lets you choose between keeping things original, adding subtle upgrades or managing budgets on everyday maintenance.
DelaVilla
DesignTek
Fibre Glass
FibreTek
Jacquemond
When should you review or replace your Porsche rear bumpers?
Checking rear bumpers regularly helps you spot impact damage, warping or age-related deterioration before it affects appearance, alignment or leads to more expensive body repairs later on.
- Existing bumpers are scratched, cracked, distorted, poorly repaired or missing trims
- You notice poor alignment with the rear wings, lights or engine lid after bodywork
- The car has had a body conversion or widebody kit and the old bumper no longer fits correctly
- Paint is badly faded, peeling or weathered compared with the rest of the Porsche
- You want a sportier, GT or OEM-look bumper to improve appearance or originality
- You are preparing the Porsche for sale and want the rear end to present cleanly
If any of these apply, it is a good time to review your rear bumpers and replace anything that is past its best so your Porsche stays smart, structurally sound and enjoyable to own.
Explore Porsche rear bumpers with Design911
Browse rear bumpers for Porsche at Design911 — from individual parts to complete conversion kits — and find options to suit repairs, upgrades and full restoration projects.