Sent you a PM but figured this could be useful for future searches as well:
So I ran CCS for a good year. At first it was fine and I used the bench flash tune they had. They switched me to their HP Tuners handheld and that's when I had problems. Truck still had lots of power and decent fuel mileage however I had a crazy turbo surge issue. They did try various things to fix it, we even did a dealer visit to factory ECM AND TCM reset and then reloaded the tune. Didn't help at all. They blamed mechanical issues.
Ended up getting Truck factory reset again and got a new engine and tranny tune from EOC/MRTuning. My mileage isn't as good (10L per 100km) but lots of power and no issues. I'm fully deleted EGR stage 2(Cooler gone not just the plates) DPF, SCR, CAT, muffler, resonator.
Overall, their tuning on cummins seems great. Brother has their cummins tunes. Not sure if they know the ecodiesel platform well enough. Its just a different motor from any other full size diesel. They did try to rectify the issues but I just got tired of it and switched which sucked as it was another $1600 out of my pocket. But the constant turbo surging was concerning.