I just purchased a GLC 300 and did not understand what was included in the advanced parking assist package, so I didn't get it. Now, I have no sensors to gage how close I am to the wall when I pull into my garage and I have to get out of the car to look because it's a tight fit. There are apparently sensors on the front of the vehicle used for other features but not parking. Does anyone else have this problem and if so, are there any options for aftermarket sensors that do not interfere with the other sensors? Appreciate any help.