I have a 99 Camaro and I want to upgrade the head unit in my car. I want to spend up to $300 for a unit. Doesn't have to be new I just want a decent unit. As for features I'm looking for GPS/Nav, Bluetooth, 32GB SD Card support, SD Cards Playlist support. aux, USB. The unit I have now has everything but the GPS/Nav but it's a terrible unit and the shop that installed it kind of screwed mover. What unit do you guys suggest? Also a very important thing I'd like on the unit is a standard volume knob. I don't like to have to push a button to raise the volume.