Audio gateway
I have 2005 e55 and my agw just went bad. My audio gateway was in the left trunk area behind trunk hinge. Pain to get to remove but I was able to do it. Found agw (audio gateway) online at eBay at a site that had a warranty on it for 245 dollars. For 300 bucks from merc sounds like a good deal. It's my understanding if u install it urself they will not honor any warranty with it. The gasket on tail light is an easy fix. Scale from 1 to 10 I would say a max of 2 but the agw is about an 8. There are so many wires hook up to this audio gateway, fiber optics if you have MOST system in your car. It looks daunting when you first did into it. I would say try to find out where exactly your agw is located. Sometimes they have it in the passenger footwell behind your carpet and metal plate. If its in a location other then that damn trunk, it may not be to bad to do. Welcome to shot any comments or questions you may have and if you cannot find out where it is, send me exact year and make model, whether u have fiber optic system or not and I will gladly help you. Just let me know!