2018 C63 S Sedan Year 1 Service
 

Just turned 1 year old and in for the prepaid 1st year service. They did whatever they were supposed to do an advised they did the recall/upgrade to the latest engine software. Comfort and S+ do feel a bit different but I would not be able to really quantify or say how, just a bit different. I tried S, a setting I had not been using as the 4 to 3 downshift was a bit rough, and although I liked the first gear starts the snap, crackle and pop in S+ was more music to my ears. Now... S mode the downshift is quite smooth from 4 to 3 and no snap, crackle and pop at all, and as far as I can tell no rev matching on downshifts....... until S+... then it seems the same as before.

Any opinions on this guys?

I just went through mine as well and have commented in several places in the forum. It was obvious to me that something changed in the transmission - seemingly quicker, smoother and slightly lower shift points. It basically eliminated most of the issues I have complained about for the past year. Since I upgraded tires, I am enjoying the better ride and traction as well. All told, I felt like I received a different car. The pops are still there so can't tell a difference there. I always drive in S+ engine mode and S suspension.

The transmission is adaptive and alters shifting behavior based on how you drive over time.

Whenever the dealer updates the ECU/TCU, it resets this adaptation back to the factory default. The difference you are feeling is the difference between your adaptation and the default one.

Interesting.. will see how it progresses from here and if that rough downshift returns.

I had thought the same, but in fact it was not the same as when I just purchased the car. If anything, the shifting better matched how I thought it should behave rather than how it had been. For me it was an improvement over stock. You will see some of my remarks in the forum just before the update about the shifts.