Kooks 1-7/8 GREEN catted oem connection vs high output

[Da Pony]

I am considering Kooks 1-7/8 long tube headers for my 2025 Mustang GT Performance Pack with Steeda H-pipe and active valve exhaust, I plan on staying naturally aspirated.

I'm trying to decide between:

- GREEN catted OEM connection pipes
- H.O. Green catted connection pipes

For those who have experience with either setup:

- How noticeable is the sound difference?
- Is the H.O. setup significantly louder or raspier?
- Any noticeable increase in drone or exhaust smell?
- Which would you choose for a street-driven car that still sees spirited driving?

Thank you in advance!

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[Da Pony]

American Muscle recommended the standard performance catted connection pipes with OEM adapters instead of the green cats. It’s about a $550 price difference.

For those running Kooks long tubes on a 2024+ GT, what are the real-world differences between the standard catted connection pipes and the green catted version?

Mainly curious about:

• smell difference
• sound differences
• CEL/issues
• performance impact
• emissions readiness
• overall worth of the extra cost

 

[Q6543]

If I understand what you’re talking about, the factory connect use your stock resonator/X pipe, the other connection is for true dual 3” custom install

 

[svtrichie]

The Kooks performance cat is for naturally aspirated and for up to 550 rwhp. The Green cats are for power adders up to 750 rwhp. The HO Greens are for up to 1000 rwhp.

We have adapters that go from our connections to either the factory 2.25" up to 3". We also make a fantastic 3" Ultra X or 3" H pipe which would be the best setup. Best would be to give Kooks a call and we can discuss what your plans are with the car. Rich@Kooks 704-768-2288 ext 106

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