Ok two things.
1. When I took my intake manifold and heads off my 530i I busted one of the knock sensors where it connects to the block. Just do one of them, its not a part that is supposed to fail ever so getting all of them is a waste of money. Cheapest place I could find them was www.autohausaz.com and I think they were like $120.
2. When I put my engine back together, I also had an extra wire with a connector one it. Apparently it is supposed to be extra if you car has ACS.
Hope that helps![]()