I had my car in yesterday for a B maintenance and a few other things. One thing I had them check was the transmission, as it seemed as if it was shifting hard. There were no fault codes found for shifts outside the normal parameters. However, he said there was a new software update for the transmission, so they updated it.
It's like a different car! And, I'm not referring to resetting the TPU different. It's amazing! Most impressive is that the initial throttle lag is completely gone. It's 100% responsive as soon as you touch the throttle.
To be fair, the throttle lag is "planned" in the name of comfort. Keeps your passengers from hitting their heads on the headrest when you accelerate.
That said, it's like I've added a tuned ECU- the car is totally different. I would recommend taking your cars to the dealership for this software update.
I'm under warranty, so there was no charge. I don't know what it would cost out-of-pocket, but it only took minutes.

 

I have done this update on my 2014 C300 as well at a dealership about half a year ago, and it does feel great.
Did not cost me anything since I was under the warranty.

When the transmission software was updated, there was also another change.
Now in manual mode, the speedometer lets me know to upshift to a next gear with an arrow sign.
Thought it was cool, but not really necessary in my opinion.

 

Where is the arrow? And, does it seem accurate to you?

 

The arrow comes up next to the gear symbol.
(Let's say you're on S1 or E1, it shows/tells me 2↑ to shift up to a next gear in green color, if I remember correctly)
It seems accurate, but I never shift that early that it tells me to for spirited driving.

 

It's what the c63 has, I was reading my manual, familiarizing myself with my new to me 2013 C300 and the pictures showing the AMG model show the up-shift arrow you describe, so the "function" has been around a while. The transmission lag is certainly there, but I guess I've grown used to it having driven a W208 for a while now.

 

I'm assuming this wouldn't apply to anyone with a 2012 w204 or older?

 

Generally, I got used to it. I just press the pedal a bit earlier or go into M mode to avoid the lag totally.

 

I would guess not since the transmission is different (different fluid, different name etc).

 

I have a 2012 c350, I'm wondering about the tranny being different, I use the blue fluid but not sure of the different name. could u explain please. Thanks

 

Too bad this doesn't apply to Pre FL (2008-2011) models.

 

What's the software number/code they installed? Did they list it on the bill ? Or can you go to your engineering menu and see ?