I have this tuner and it works great on my 2020 6.2. The performance gains are very noticeable with the 91 octane tune. There are Youtube videos with actual tested performance increases. I also have the performance package, so maybe that makes a difference. I test drove a new 2024 AT4 with the "active" exhaust and the power / acceleration was noticeably less on the new truck and I am running 35" tires.