After many attempts to solve my 2014 Mercedes c250 rough idle, replaced plugs and coils, rough idle continued, check engine light remained illuminated. Diagnostic codes said misfire on cylinder 3, I finally contacted The Ecu Pro. The process was very simple, the website was easy to use, they were professional, honest and courteous whenever I called for information. Shipped my ECU via UPS, ECU was tested and determined to be the cause of my vehicles misfire. They sent via FedEx a replacement ECU. Entire process took approx. 8 days. My benz runs like new. Saved me big, big, money. Will definitely use them again if needed. Highly recommend. Much thanks ECU Pros