Is your starter issue intermittent (without your grounding work around of course), and do you have any other intermittent electric issues accompanying your start issue? I have an automatic n63 engine that developed intermittent start issues, transmission faults and random symptoms like the Idrive and even the engine shutting off. These multiple symptoms led me to replace the IVM which is apparently common with many 2003-2011 models. I only saw on replay generally mentioning relays, so I thought I’d ask. Also one person mentioned the IBS, I believe all you need to do is remove that extra cable from the negative battery terminal to test that. Good luck, and my starter is definitely bad and I’m having a hell of a time with the manifold removal (is it just 4 nuts?) any advice would be appreciated.