Converting A ’10-’12 Mustang Rear To ’13-’14 Spec

It doesn’t take an expert to recognize the beauty found behind the rear wheels of the brand new 2013 and 2014 Mustangs. Not only do these modern muscle cars offer LED sequential taillights, they also offer sleek blackout panels on the trunk, a sporty rear valance and even an updated rear bumper. So what happens if you have a 10-12 Mustang but desire the design cues of the latest and greatest?

Well, like us, you opt to upgrade the rear end design of your current ride. But that’s not all we did to our 2011 Mustang, Project Wild E Coyote this time around. Helping us paint match our new bumper was JEP Autoworks.

Wanting a more powerful exhaust sound, we also opted to equip the car with a CORSA Performance axle-back exhaust system, filling out the new GT500 rear valance nicely with it’s quad-tips while giving the car a crisper muscle car exhaust note. There was just no going wrong with this upgrade!

These are the main, large pieces that support the bumper and taillight conversion.

Ford Parts List

This conversion can be performed with a 2013-14 Mustang GT bumper for single exhaust tips or a as in our case a GT500 rear bumper to allow the use of large diameter tips, or quad-tips like the factory GT500 utilizes. We’ve compiled a list of the Ford specific parts you’ll need below, simply substitute in which bumper cover parts you’d prefer and order accordingly.

2013-14 GT Appearance Specific

  • DR3Z-17K835-APTM Rear bumper 13 GT
  • DR3Z-17C830-AA Lower bumper molding (not needed for GT500 valance)

Needed For All

  • DR3Z-17B390-AA License plate pocket
  • DR3Z-17A955-AA Lower bumper bezel
  • W611103-S424 Right side screw retainer
  • W611103-S424 Left side screw retainer
  • DR3Z-17788-A Impact Absorber
  • DR3Z-63423A42-EA Trunk finish/black out panel (optional)
  • DR3Z-13404-A Right tail lamp
  • DR3Z-13405-A left tail lamp
  • Dr3z-15A448-A Right bumper reflector
  • Dr3z-15A449-A Right bumper reflector

2013 GT500 Specific

  • DR3Z-17K835-APTM Rear bumper GT500 (or modify GT bumper)
  • DR3Z-17F828-AB Lower rear bumper cover
  • W716460-S300 Lower cover clip (2)
  • W716237-S300 Lower cover retainer (2)
  • YL8Z-16K262-HC Lower cover fastener (2)
  • W705436-S300 Lower cover pin (2)
  • W707291-S439 Lower cover nut (2)
Combining Components for the Ultimate Rear End Upgrade

With the latest design cues in mind, we took to the web to track down everything we needed to convert the rear end of our 2011 Mustang into that of a more modern muscle car. Our parts list included a 2013-2014 GT500 rear bumper with a corresponding longer, lower valance, a license plate pocket, bezels, mounting brackets, and all the associated hardware, including the side retainer screws, bumper clips and rear bumper foam.

We also picked up the 2013-2014 sequential taillights through a used parts source, and a CORSA Performance axle-back exhaust system from the famed performance exhaust company itself.

Thanks to a previous upgrade to MMD taillights back in the day, our 2011 Mustang already sat equipped with the trunk blackout panel, but had we needed to also supply this component for our current upgrade, we could have used the 2013 Mustang blackout trunk panel by removing the included tabs and securing it to the back of your car using double-face tape like 3M body adhesive tape.

Checking In with CORSA

The CORSA axle-back system features 3-inch exhaust pipe, dual rear exits and twin 4-inch polished Pro Series tips. The system is six pounds lighter than the Mustang’s stock setup and gives the car about 43-percent better air flow, freeing up around 16 hp and 21 lb-ft of torque on a stock engine. Given Wild E. Coyote’s recent major upgrades under the hood, this system is just what we need to ensure that hot turbo exhaust gas finds it’s way out the tail pipes in a timely manner.

To get an idea of how the CORSA exhaust system we had chosen would enhance our rear end conversion, we contacted CORSA’s Brent Noward. “A CORSA Performance exhaust is designed to offer an aggressive sound at idle and under acceleration, and a drone-free experience at cruise,” Noward explained. “[It] is for the individual who wants their car to sound like a muscle car when they want it to, without sacrificing the interior cabin experience.”

CORSA Performance exhaust systems offer what the company calls NO DRONE Reflective Sound Cancellation technology, or RSC. This patented system allows CORSA to offer an upgraded exhaust note outside your vehicle without adding any noise to the interior of the cabin thanks to a free-flowing, unrestricted air path in the exhaust system. This straight-through system advancement also allows for significant horsepower and torque gains.

MG3_8190While no one can argue with a better exhaust note and added performance, CORSA puts the cherry on top of an exhaust upgrade by offering strictly bolt-on exhaust systems like ours. Not only does this mean that even individuals with little to no experience in installing exhaust systems can successfully upgrade their vehicle on their own without the need of special equipment, it also cuts down on the time needed to do an exhaust swap and ensures a precise fit.

This is just a small part of what Noward explained is CORSA’s goal to provide their customers with an amazing experience with their new exhaust system straight from the time they open the box.


2013 Mustang taillights on a 2011 bumper

With performance, sound, and design improvements all within view, we moved forward with the upgrades to our 2011 Mustang. And although these upgrades were set to make a big difference in all areas for our modern muscle car, since all of the body pieces necessary to achieve our Mustang’s revival were OEM Ford parts everything was plug-and-play!


The rear bumper cover is shaped differently on the 2010-12 versus 2013-14, leaving a large gap below the taillights.

One of the reasons we chose to upgrade the rearend of our Mustang from a design standpoint is because of the way our 2013 sequential taillights looked with our existing bumper. While to a passer-byer it may not be overly noticeable, to the trained eye a gap between the taillights and the bumper can be detected.

To begin our upgrade, we removed our modern taillights by merely pulling back the trunk liner from inside the tail panel, which gave us access to the hardware securing the lights to the rear of the car, and unbolting them from the rear of the car. With the wire harness disconnected at the taillights, we unbolted the taillight housings and slipped them off the back of the Mustang.

Removing the rear taillights is as simple as moving back the interior trunk panel and unscrewing the taillight housings from the rear of the car.


Next we pulled off the old bumper, accessing the screws and pins holding the bumper in place along the inner side of the taillight compartments and on the underside of the bumper. After disconnecting the wiring harness for the rear sidelights, the bumper and rear valance slipped off the back of the car in one big piece.

Removing the rear bumper on the 2011 Mustang was just as simple as removing the taillights. All it took was loosening a few screws, unhooking a wiring harness and pulling off some clips.


After we had everything taken off the back of our Mustang, we fitted the car with its new bumper. We purchased the complete GT500 bumper, bumper support bracket, and taillights from a local used parts retailer for $1,000. It’s easy to find the taillights used for around $650-$900 a pair, though the bumper components can be a little more difficult. The bumper was originally white, so we took the bumper and bumper reflectors to our local paint professionals, JEP Autoworks. Using our VIN number, JEP was able to match our paint perfectly and looks as good as stock.

First we replaced the bumper mounting brackets, which attach right to the factory holes on the rear of the vehicle, using the factory hardware. We then attached the new bumper foam to the metal bumper of the car with the existing push pins, which was suitable for both our old and new bumper, before attaching the new GT500 bumper in the old component’s place.

IMG_6093Attached to the new bumper, we reused the Mustang’s original sidelights, license plate lights and wiring harness since they are the same on both the GT and the GT500.

With these in place, we plugged in the lights to the car’s integrated wiring harness and proceeded to attach the bumper using the same mounting holes as before.

In addition to the mounting hardware, which mostly transferred over from our previous bumper, we transferred the bumper clips to keep the bigger GT500 bumper in place. We also added ROUSH rear side splitters, part number 421405, which the bumper was already drilled for when we purchased it. Still, the included template helped ensure our holes were drilled in the proper locations. These side splitters give the car a little extra detail that works nicely with the ROUSH side skirts already installed on the car.


While our rear bumper upgrade certainly looked good on its own, it did nothing for the sound or performance of our ’11 Mustang. Thus, we couldn’t wait to get our CORSA axle-back exhaust system installed!

The final steps to the aesthetic upgrade included reattaching the sequential taillights, which now fit snugly up against the bumper, and attaching the license plate pocket. We also installed a back-up camera while we were back there.

High-Tech Exhaust Install

Soon we will be adding American Muscle’s taillight tint to add a sleeker look to our dark, Sterling Gray Mustang.

Once the rear bumper upgrade was finished, it was time to equip the Mustang with the CORSA axle-back exhaust, part number 14321.

Just like our bumper upgrade, the CORSA exhaust upgrade was plug-and-play. After detaching our old single-tip axle-back exhaust system by loosening the coupler and pulling the system out the bottom of the car, we were able to simply put the CORSA system directly in its place without any cutting or welding. To attach it, we used the included couplers to attach it to the exhaust pipes before pushing the integrated stabilizers into our already mounted bushings near the exhaust tips, completing our exhaust system.

While this bolt-on exhaust system packs quite the punch, CORSA recommends installing an XO-Pipe for the best performance results. We opted not to install an XO-Pipe this time around but for those looking to do a similar exhaust upgrade should consider using an XO-Pipe in addition to their CORSA axle-back exhaust system to free up even more horsepower and torque.

Final Impressions

With the bumper upgrade complete and our CORSA Performance exhaust upgrade done, our 2011 Mustang looked as sleek as ever. Not only is the rear end more streamlined than before, it is also upgraded to reflect the positive design upgrades found on the latest Mustang models.

Of course, the bumper upgrade would not be the same without the CORSA axle-back exhaust system to not only fill out the GT500 rear valance, but also improve the look of our exhaust system and the overall performance of our modern muscle machine.


Article Sources

About the author

Lindsey Fisher

Lindsey is a freelance writer and lover of anything with a rumble. Hot rods, muscle cars, motorcycles - she's owned and driven it all. When she's not busy writing about them, she's out in her garage wrenching away. Who doesn't love a tech-savy gal that knows her way around a garage?
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