So a friend of mine has an '05 TL and she had brought her car someplace to have some subs put in the trunk. The place told her not to do it because the built in navigation receives its signal from the rear window and that the bass from the subs would interfere with the signal. This sounds awfully absurd to me. I know that the antenna for the stereo is built into the window, but i find it hard to believe that the GPS signal has anything to do with the rear window or if it does that it would be interfered with. Does anyone have the stock navigation still installed and is also running subs that can tell me if this is even slightly true? Thanks.