Can anyone help me with the choice of MB Star diagnostics I should choose. There are 3 or 4 versions listed on various websites. I.e. MB Star C3, C4 .. I even found a website with a C5. Some if them list Xentra or Developer not 100% sure what these are, I remembered reading a thread about rear LED light retrofits where Developer was needed??? Can someone educated me, or even suggest a device, xixal