Hi I have a 2004 z4, i have a problem when opening the roof. when i press the button the roof opens about 5cm then i need to gently push it up while pressing the button for it to open. feels like it doesn't have enough power to pull it up. when i close the roof it works perfectly. if i need a new motor how much would it cost. Also i have some moisture building up in the head lights when i wash the car and usually dries out if its a sunny day. if you can please help it would be very appreciated