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UPR has been building Mustang and drag racing parts for over 35 years, which on the S650 counts for more than it sounds. The independent rear suspension carries over conceptually from the S550, so UPR arrived at this platform already knowing where it flexes and what breaks.
Two categories matter most on a 2024+ GT or Dark Horse: a catch can, because every direct-injected engine wants one, and the IRS components that stop the rear suspension moving in ways it should not.
Catch Cans
When fuel burns it produces gases. Most leave through the exhaust, some push past the rings into the crankcase. That is blow-by, and down there it mixes with oil to form sludge and vents up through the PCV valve into your intake, manifold, valves and intercooler.
A catch can catches that material and holds it instead of letting it continue into the engine. It does not add horsepower. What it does is stop you losing the horsepower you have as carbon builds on the intake valves, and keep a custom tune behaving the way it did the day it was flashed.
UPR's are plug and play for the platform, built from billet aluminum, and install with basic tools. Maintenance is checking and emptying it, which takes about as long as checking your oil.
Billet aluminum construction
Multi-stage filtration
Many models include a drain valve
IRS Components
This is where UPR's drag racing background shows. The S650's independent rear is good at ride quality and less good at putting power down repeatedly, because rubber bushings and a subframe that moves within its own mounts both allow deflection. Every part below removes some of that.
Subframe Braces
The IRS subframe flexes. Braces reduce that flex, which means more precise handling, better power delivery and more stability under aggressive driving. They also reduce wheel hop, which is the audible version of the same problem.
Subframe Alignment Kit
Squares the IRS subframe to the chassis. From the factory there is enough tolerance in the mounting that the subframe can sit slightly off, and everything downstream inherits that error. This is the part that makes alignment settings mean something.
Adjustable Toe Links
Precise toe adjustment, which does two things: it optimises tire wear, and it firms up cornering stability. If your steering feels vague at the limit, the rear toe is a likely culprit.
Vertical Links
Minimise suspension deflection, which translates directly to traction. Less unwanted movement means the tire stays planted under hard acceleration and through corners instead of the geometry changing while you are loading it.
Cuts wheel hop
Better power delivery and stability
Makes your alignment settings meaningful
Do this before chasing handling elsewhere
Optimises tire wear
Sharper cornering stability
More traction, more predictable handling
Billet aluminum
Urethane, so no added harshness
Cheap fix for a real problem
Essential once the car is lowered
Billet construction
What to Buy First
If you buy all of the above at once you will be happy. If you are working through it over time, this is the order that gives you the most improvement per dollar.
- Catch can. Not a performance part, but the one that protects everything else. Do it now regardless of your goals.
- Subframe alignment kit. Cheap, and it makes every alignment and geometry change after it actually mean something.
- Subframe braces. The biggest single reduction in wheel hop and rear-end vagueness.
- Toe links and vertical links. Now that the subframe is located and braced, these let you control the geometry precisely.
- Camber arms and diff inserts. Finish the job, especially if the car is lowered or seeing track time.
Frequently Asked Questions
Does a 2024 Mustang GT need a catch can?
Every direct-injected engine benefits from one. Blow-by carries oil and unburned fuel into the intake tract, and a catch can holds that material instead of letting it build on your valves.
Does a catch can add horsepower?
No. It prevents the gradual power loss that comes from carbon buildup, and keeps a custom tune behaving consistently. It is protection, not a power adder.
What actually causes wheel hop on an S650?
Deflection. The IRS subframe flexes within its mounts and the bushings allow movement, so the rear geometry changes while you are loading it. Braces and stiffer links remove that movement.
What is the single best first suspension mod for the rear?
The subframe alignment kit, because it is inexpensive and it makes every subsequent alignment and geometry adjustment accurate. Then the subframe braces.
Do UPR IRS parts fit both the GT and the Dark Horse?
The IRS components listed here cover 2015-2026 Mustang, which includes S650 GT and Dark Horse. Always confirm against your exact car, especially if it has the Performance Pack or Brembo brakes, since some parts have brake-specific versions.
Will I need an alignment after installing these?
Yes, for anything that adjusts toe or camber. Toe links, camber arms and the subframe alignment kit all require it.
Are UPR catch cans hard to install?
No. They are plug and play with no permanent modification, and all necessary hardware is included.
Keep Reading
Stop the Rear End Moving
Catch can first, then take the deflection out of the IRS. 35 years of drag racing knowledge, applied to the S650.
