Need some advice. When I placed my E 500 order, It showed Navigation and the total price of the car had navigation included. I picked up my car last week and asked the salesman when he thought the Navigation would be installed in my car. His answer was " When it comes in, You can buy it and we will install it "..When asked about the fact that I had prepaid for it, His response was " thats why we gave you $ 1,500 off of MSRP " Now I was offered up to $2K off sticker from another dealership but turned it down as the one I bought the car from was closer to my house and offered MB Loaner cars.........Who here Pre Paid for the Nav system ??? and has anyone else hada this problem.