Ok so new battery installed and plugs too so now to the questions that probably have been asked millions of times.

1. Do you drive yours in Auto 4wd or 2wd? Which is better for the vehicle/tranny/transfer case and which is better on milage?
2. Have you replaced your exhaust system? Mine is going out, you can hear the rattling of the cat somewhere.
3. Can I bypass the stereo mid console and hook up headphones directly to the above dvd player? Previous owners killed all the switches.
4. Someone installed a weird switch for the stereo. It's a toggle and it loud one way with ipod but loud other way with regular radio. What the heck?