2018 Mercedes-AMG C63 — dyno numbers changed more than the car feels

I'd keep this practical. Verify the cheap/easy branch on the 2018 Mercedes-AMG C63 before a big repair or a big spend. I'd do that before spending real money. Learned this the expensive way on a previous car. Doing the boring step first on purpose.

Write down what you already tried. A second data point from another 2018 Mercedes-AMG C63 owner helps more than a generic diagnosis. Then you'll know the next fork. If they can't show the line item, I assume it's hiding. Might be overthinking it, but I'd rather overthink than overspend.