Steeda S550 IRS Alignment Bushes - Mach One / GT350


Steeda Europe has always said that the Steeda IRS base kit is THE Must-have starter mod for every single S550 Mustang, and now Mach One owners and GT350 owners can see the benefit as well... Eliminate wheel hop with no added NVH to optimise and improve your Mach One's performance.

Please note all prices here are estimates and vary depending on size / weight and location.

As a guide, UK Mainland are all addresses not in Northern Ireland, but does include Islands, and Scottish Highlands. Delivery to "Highlands & Islands" can take a few extra days.

EU deliveries cost varies on service requested and weight / dimensions. Normal quote is via the cheapest "standard" delivery. Small Package delivery option is available for EU deliveries under 2 Kg, ideal for small parts.

Local Pickup can only be used in prearranged circumstances, e.g a car show etc.

FREE SHIPPING is available on order over a certain amount (country dependant)

Delivery Service   Time  Price inc VAT
Royal Mail Registered (small items) UK 2-5 days £4.98
Royal Mail Registered (small items) 1-2 days £9
Parcelforce / UPS / DPD / DHL UK Mainland 1-2 days £11.40
Parcelforce / UPS / DPD / DHL Overnight, pre 9am, or AM 1 day  varies on option - ON REQUEST


If you have issues with damage through shipping it is ESSENTIAL that we get photographs as it is impossible to take up the case with couriers without proof of damage. The following will be required, further pictures may be required.

1. Pictures of the shipping label (e.g carrier shipping label)

2. Pictures of the damaged packaging (if applicable)

3. Pictures of the damaged item


Steeda Europe has always said that the Steeda IRS base kit is THE Must-have starter mod for every single S550 Mustang, and now Mach One owners and GT350 owners can see the benefit as well...

The full 555-4437 IRS Subframe Support kit does not fit on the GT350 or the GT350 inspired Mach One due to their revised factory setup, but they can still benefit from the improvements that this kit offers.

Why, you may ask? Well, a performance focussed car like a Mach One (or GT350) is all about control and speed. This kit will help you maintain control and prevent traction loss due to wheel hop. This is one of the first and most simple steps that should be taken to eliminate wheel hop. It is recommended that you also install the Steeda subframe alignment kit at this time because you will already be working in that area.

Eliminate subframe movement. The Steeda IRS subframe bushing support system eliminates the rear subframe movement that is notorious in the S550 Mustang platform. Stiffening the subframe and preventing movement is the way to reduce and eliminate the troublesome wheel hop that plagues the Mustang when launching or taking tight corners.

Enhanced road-feel. Installing the Steeda bushing support kit gives the driver a better feel for the road, letting the driver feel connected to the car. This makes spirited and track driving more enjoyable and more responsive.

No Increase in NVH. Drive comfortably on the street with the Steeda bushing support kit. The bushing supports add no NVH to your Mustang so that your highway cruising and in-town commute are as comfortable as they were on your stock Mustang.

Quality construction. CNC machined in Steeda's Valdosta, GA facility from T6061 aircraft grade billet aluminum for the highest quality construction.

We highly recommend adding our Mach One / GT350 specific IRS base pack or full pack to further hone your street and track weapon! Select from drop down...

Features & Benefits:

  • Increases traction
  • No increase in NVH
  • Better handling
  • Enhanced road-feel
  • Easy to install
  • No permanent modifications
  • Made from billet aluminum
  • CNC machined
  • Lifetime warranty
  • Same patented design as the 10-piece kit (for standard S550s)

Part number: 
555-4449 - Mach One (& GT350) Subframe Support Bushes
555-4451 - IRS Base Pack for Mach One & GT350 - (adds the IRS alignment bushes 555-4438)
IRS-PACK-FULL-MACHONE - (adds the 555-4438 alignment bushes and the 555-5754 IRS subframe braces)

Fitment: 2016+ GT 350 and 2020 + Mach One

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