New ISF owner and I have some questions.

first off I have an 08 Mercury Metallic with 23k miles and owned it for almost two weeks and here are my questions:

1. Does anyone know how to adjust the voice navigation and bluetooth audio as far as where the voice is coming out of the speakers? When I am on the phone or am using the Nav, the voice comes out the drivers side only. I would like to change that if at all possible.

2. Rain sensing wipers.
I seem to have an issue with these and I brought it to the dealer for them to try and fix but they said they could not find anything wrong with it. What is happening is when I get in the car in the morning the wipers will start wiping all by themselves when there is no rain. They wont shut off until I manually do it. Then when it is raining they don't wipe often enough even when I adjust the sensitivity. Has anyone dealt with this themselves? If so what was your solution?

3. Mark Levinson subwoofer.
When I bought the car CPO I found out on the way home that there was a rattle coming out the back when I played the stereo. Upon further investigation I discovered that it was a blown speaker. I had the dealership swap it out for no charge. Now it is a nice setup but the bass is too weak. It is a surround sound setup for DVD audio which I have a few DVD audio discs. When I play those discs the system sounds fantastic! The DVD player will filter the audio into 5.1 surround like it is designed to do. However when I listen to regular audio cd's (stereo) or music from my ipod the sound is good but not as good as the DVD audio (of course) As a result I have to turn up the volume a bit more than normal and the subwoofer is not strong enough to handle it. (which explains the blown sub from the previous owner) **my question** Has anyone had this issue and if so what have you done to resolve it?

Thank you all for your time and responses.