I purchased my r56 non turbo at an auto auction so my knowledge is limited on the vehicle.

I just replaced the battery because the one with the vehicle was WAY too small and was not the right one.. I also wouldn’t crank because it was dead.

but since I had the car I received 2 keys, one all black and one with a white rim around it. The key with the white rim starts the car, but the radio doesn’t work with it (I am not sure it this is a related issue). The all black key makes a grinding noise when starting the car a bunch of times then it finally cranks and starts. If I go from the black key that doesn’t start the car, then insert the white rimmed key that normally starts the car, that key makes the grinding noise too. I don’t know if the car has an electrical issue, or if just the starter is going bad. Here’s a link to the noise, which sounds like a starter to me, but doesn’t make sense that it starts with the white key.
has anyone experienced this issue?

 

The keys don't matter , its not a hellcat .. sounds like you have electrical issues. Grinding when starting sounds like start issue (can't play your video in the office)