My car came w/EC tune. I still have the file. Then I got a V-Tech Georgia (the country) tune. They are well known on MB forums and Facebook groups. On my other vehicle I have the Mercedes Swap Shop tune. Both are great. And both blow EC out of the water.
Compare to EC, these two tunes run like day and night. I understand EC is known for being "conservative" but I have not heard any issues with Vtech or MSS at all.
For TCU tunes, MSS is THE best. They offer the 4-mode TCU tune. You will be able to adjust the way you car shifts with the S/W switch next to the shifter. There is Agility (A) Mode, Comfort (C) Mode, Sport (S) Mode and Manual (M) Mode. If you click S/W in whatevr Mode you are, the gear display shows what gear you are currently in and prompts you to shift up if you are in Manual mode. Btw, if in true manual mode, it will ONLY shift when you want it, too. So it's the closest to a true manual gear you can get.
Love it. Really woke up the Transmission. Can only recommend, especially for SRTs but I'm sure even N/A will see quite a big difference.

You can always buy the Latemodel21 paddle shifte kit and oh boooooy. It's fun! He can also supply the TCU tune together with the paddle shifter kit. And it's relatively easy DIY