It's best to go in person because if you try to call, they'll put you on hold/send you to voicemail, or if they're feeling generous, the receptionist will admit they're busy and unable to help you but you should make an appointment. They offer to call you back another time which isn't a problem normally, but sadly they do not actually call you back. Really not the type of service you want from a brand like BMW. Customers shouldn't have to make a long trip to your dealership just for one or two questions. I currently have 3 BMWs so it's not like I'm a new customer who is just pestering you with no intentions to buy. Goes to show that once they successfully sell you the car, they want you out the door ASAP to make room for other sales. Your questions are now no longer as important as when they were still trying to sweet talk you in sales. Money is good anywhere, not just BMW. Spend it elsewhere!