cas, you only got this car in April and remembering all your thread since then, you already have so many problems with it. Interior lights dim, electronic hang, vibration when turning left, airbag indicator light, RPM drop, now 1 litre per day water leak! You also spend money at M-speed on your angel eye and not satisfied with result.
I'm sorry to tell you you bought the wrong car friend. It's an expensive lesson to learn with your 1st car, but the BMW gods were not kind to you as someone wish for you when you told that you bought the car without testing it. Best thing to do is to cut loss and try to sell it now. Then go and buy a simple car and take a knowledgeable person along to test the car before signing on the dotted line. BMW comes later when you know more about cars. Even experienced people have trouble maintaining a BMW. Sorry lah cas, these things happen.