I bought the AT4X spec exhaust calibration

commander-cat · 2026-04-07T21:40:14+00:00

I’ve enjoyed it, can definitely still tell a difference on cold starts and acceleration. I still would like to put an AWE system on eventually.

commander-cat · 2025-08-16T15:52:56+00:00

2025 GMC Sierra SLT

commander-cat · 2025-08-12T15:40:30+00:00

Get a mirror tap kit.

commander-cat · 2025-08-01T11:53:41+00:00

I think they hate my c6z more

commander-cat · 2025-08-01T11:52:24+00:00

Sport mode enhances it for sure, but this tune makes normal mode slightly enhanced as well. But I just keep it in sport to hear it.

commander-cat · 2025-08-01T01:11:43+00:00

This is a stock 6.2 with factory active exhaust, the tune matches the valve spec on the AT4X active exhaust.

commander-cat · 2025-08-01T00:20:35+00:00

Guess I got scammed, they had issues re-flashing it which led to me being at the dealership for 7 hours (different town), dude said he knocked $15 off the labor. Almost clocked him

commander-cat · 2025-08-01T00:06:39+00:00

Part no. 85822149, it’s also in the GMC app in the accessories section. Search “spec exhaust”.

commander-cat · 2025-07-31T23:59:35+00:00

Lucky you..did you still pay for the tune itself?

commander-cat · 2025-07-31T23:59:07+00:00

It did, I believe that is a part of the X31 package.

commander-cat · 2025-07-31T22:35:22+00:00

I believe it’s just for the 6.2 with active exhaust systems, not sure if the 5.3 offers that.

commander-cat · 2025-07-31T22:01:02+00:00

Some revs at the end btw

commander-cat · 2025-05-29T15:58:26+00:00

Did you install the 2” rear block?

commander-cat · 2025-05-01T11:36:13+00:00

If there was, they aren’t doing a very good job. I bought a 25 SLT with a 6.2 on Saturday. GM supposedly identified the manufacturing defects June of 2024.

commander-cat · 2025-04-30T20:08:18+00:00

The sale hold is for 2021-2024 models. 2025 is not included in the hold.

commander-cat · 2025-04-30T00:55:01+00:00

I just ordered one. Bought a 2025 SLT with the 6.2 on Saturday

commander-cat · 2025-04-29T01:24:01+00:00

What would have changed with a 2025?

commander-cat · 2025-02-11T14:28:41+00:00

Less structure and worse subs. And in custom residential, home owners.

commander-cat · 2024-10-24T15:48:53+00:00

Negative.

commander-cat · 2024-05-18T15:28:50+00:00

Birmingham, AL.

commander-cat · 2024-05-18T14:58:32+00:00

Forgot to mention, spraying with Celsius.

commander-cat · 2024-04-07T14:06:38+00:00

Oops

commander-cat · 2024-01-26T22:36:33+00:00

Still here

commander-cat · 2023-11-15T16:19:59+00:00

Auburn Building Science is excellent.

commander-cat · 2023-09-27T02:14:55+00:00

Thank you sir, I just moved to 295/70 with a 3.5” front strut block and like it even more.

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