This friend of mine has a body shop and own a same model as mine 02 Si. He stated that BMW did not looked into this problem when manufacturing this first SUV by them. He stated that he gets this type of problems at least 2 out of every 4 E53. He has the same problem with water after raining, it happens when you have the vehicle parked on a tilt towards the passenger side. Water will get into the passenger side floor and basically fill the carpet with water. He explained to me that water does travel thru the wires.
At first I though he was bs ing me when he said this but after loosing a second Amp. I had a towel in under the Amp and the towel did not get wet at all. However, water had sip into the unit thru the harness. I used a paper towel to wrap the harness and let it sit overnight and BINGO paper towel was wet next day.
You may want to experiment this to see if this do happens to your unit, at least you know the reason for this amp. going bad.

So he changed his amp. to an aftermarket with DVD and GPS. I don't have a need for build in GPS since most aftermarket unit are IPHONE/ANDROID ready. So I can use the GPS from GUGLE on the Iphone.

I saw the Avic model from Pioneer. I'm having a strong consideration on this model. I'm hesitant cuz, I'm looking at it this way...the car is abt 11yrs old. Over 100K. Do I want to cont. putting more money into it or do I go the short way and save for a newer model next year?

Does anyone else have a better recommendation.