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Steeda S550 Mustang Subframe Alignment and Support kit (2015-2020)

3 Review(s)
$42.00 (20%)
Steedas S550 Mustang IRS subframe bushing support system for your Mustang GT, EcoBoost, and V6 will give the rear end a solid feel with no increase in NVH at all. The bushings eliminate rear subframe movement .A stiffened subframe allows the car to incre
Part Number: 555 4450
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Steeda has come out with a kit that all S550 Mustang customers have been waiting for.. The Steeda S550 Subframe Alignment and Bushing Support System!

We combined our ever so popular 555 4438 and 555 4437 kits into a money savings combo kit where you the customer benefits! The S550's subframe mounting holes are very large compared to the subframe mounting bolts. Since there is a large difference in bolt and hole size, the subframe can be mis-aligned from the factory up to 1/2" left to right. The Steeda S550 Mustang IRS Subframe Alignment Kit is made from CNC-machined Delrin to avoid putting two dissimilar metals next to each other, preventing corrosion. Delrin is also less weight than aluminum or steel inserts and therefore keeping performance in mind. The Delrin sleeves slide into the subframe mounting holes, and fill the extra space left between the subframe mount and bolt from the factory therefore eliminating any movement. Our Steeda S550 Mustang IRS Subframe Alignment Kit guarantees that the subframe will be bolted to the same location every time it is lowered. Eliminating the need for unnecessary subframe alignments.

These Steeda S550 Mustang IRS Subframe Bushing Support System for your 2015-2017 Mustang GT, EcoBoost, and V6 gives the rear end a much more solid feel with no increase in NVH at all. The Steeda IRS Subframe bushings eliminate rear subframe movement notorious in the 2015-2019 Mustang GT, EcoBoost, and V6. A stiffened subframe allows the car to increase traction to the rear wheels and is the first step towards eliminating wheel hop. The Steeda S550 Mustang IRS Subframe Bushing Support System for your 2015-2019 Mustang GT, EcoBoost, and V6 are easy to install, with basic hand tools. The Steeda IRS bushing kit also does not require any permanent modifications to the car.

PATENT NO.: US D784,881 S

Product Benefits
  • Our IRS Subframe Bushing Support system fills in all factory voids in order to eliminate movement of the IRS subframe
  • Utilizes all 4 factory mounting locations, which completely restricts shifting or rotation (Competitors only support 2 locations)
  • Practically no added weight to the vehicle
  • Uses precision machined Delrin sleeves which adds no NVH and limits vibration to the vehicle
  • CNC Machined parts for a precision fit unlike welded and stamped parts with slotted holes
  • Aligns AND holds the subframe in place, in all 4 mounting locations
  • Easy installation, can be done in under 2 hours
  • More cost effective than others on the market to control wheel hop

CA Residents: Cancer and Reproductive Harm WARNING www.p65warnings.ca.gov.

Fitment & Features


Manufacturer: Steeda Autosports
Made in USA: Yes

Vehicle Fitment:

Fits Model Year: 2015, 2016, 2017, 2018, 2019, 2020

Customer Reviews

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Average Customer Ratings


Amazing change
My s550 is already a floppy convertible, and boy you could feel the rear end slop around on launches, and jump all around when cornering hard over choppy pavement. I use this car as a back county cruiser so I need more stability than stock offers, and the IRS is the basis of all stability. This kit changes everything. Got it on sale, along with the bump steer kit. Rear end bites, takes power much better, front end corners and holds the line around the curve over expansion joints. I am going to eventually replace most of the thin floppy stock stuff with Steeda... One part at a time. But this is the foundation of good performance: Hold everything together nice and tight.
Did you find this helpful?  2 of 2 Found Helpful
Reviewed by: (Verified Buyer)  from California on 2/15/2019
S550 Subframe Alignment and Support kit - daily driver reveiw
Installed these puppies at the same time as Steeda dual rate competition lowering springs. The difference is felt instantly as you put the car in gear, more connection, less slop, when taking sharp right turns the slight hoping is better, furthermore when launching there is less hop. These were easy to install and make a noticeable difference. On the highway the rear end doesn't feel disconnected anymore, everything is more predictable. Made my Mustang feel more like how my BMW felt. These are a must buy for any S550!
Did you find this helpful?  6 of 6 Found Helpful
Reviewed by:  from Vancouver, B.C. on 12/11/2017
Rock Solid
Put this alignment and support kit on because of the advice from Randy at STEEDA and what a difference it made. Not a bad install. Just take your time and pay attention to the videos. Definitely tightened up the subframe and takes the wheel hop out. Also put the subframe braces on. The best part was taking my car in for an alignment and got multiple compliments from the service department. Everybody was like, "You're serious about your suspension, aren't ya?" Nothing but STEEDA parts underneath. My car rides like it's on rails, and all the power transfers to the back tires with no hop. Thanks again, Randy for the honest advice. Keep up the good work STEEDA!!!!
Did you find this helpful?  14 of 14 Found Helpful
Reviewed by:  from Loganville, Ga. on 7/10/2017
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