Had the pros at ECU Pro clone my MB W203 C class EIS after my original unit suffered a mechanical failure and the key fobs stopped being recognized. The 1st unit they sent worked (car start) but threw an error code. A quick chat with technical support (and the actual technician working on the unit) and they configured and mailed a 2nd replacement out a few days later which worked flawlessly, and included a shipping label so I could mail the 1st one back for free. They stand behind their work which is very reassuring. These guys saved me a pile of $$ compared to what the dealership wanted. Phone support was very professional as well. They were able to answer all of my questions. I am a very happy customer. Can gladly recommend. These guys know their stuff.