As title states how has your experience been?

I would assume it would be similar to the w204 with pretty good gains since the car is detuned from factory.

Just curious!

These cars are very quick as delivered from the factory.

What the car needs is rear wheel traction, so look to a limited slip/ posi differential for best speed improvement IMO.

I know tuners remove the 155 MPH speed limiter bring top speed to near 180.
Not sure what the tune will actually add to performance and drivability.

Then, any smog laws for you to be concerned about at registration time?

As for "bolt on" before the tune they seem to be:
a) Modifying the Air Boxes removing the secondary carbon filter or switching to world wide OEM boxes (can't recall the exact term) which differ.
b) Headers...expensive I think there are only two brand choices.
c) Exhaust modifying...changing the cats, removing the resonator and creating a true dual exhaust.

So, not knowing your goals and budget these may be a cool $5000 worth of mods.
What is the horsepower return? 25 maybe?

Again best IMO is the differential and traction.

Good luck with your project and decision.

Let us know how the project ends up and goes.

And Blip throttle mod

I don't think throttle blip mod is accessible to our cars, well not like it is for the c63's using v5 eurocharged. According to eurocharged a tune would around 60hp. So bang for buck a tune would be best I believe.

I have removed resonator, removed charcoal filter, and add d afe pro dry filters. Would love to do headers down the road.

To answer question about traction I totally agree especially if I were tracking the car, but I don't like to launch the car or do much wot in 1st for that reason and to be careful/gentle on drivetrain, so reason for tune would me more for that 30-40 burst to around 80-90 or so give or take.

Oh take back I think weistec does blip mod for like 2k or so in our car which is crazy.