In version 2.14 of the plugin it's possible to use autocomplete on gotoaddres field, directions form etc.
See:

• From to form
• Marker with directions
• Goto address field

Here are some tips on changing autocomplete styling in general:

• Add to your template css a section for autocomple and add a definitiion for the class pac-container:
  .pac-container {
  }
• To change the color of the results, add to this definition:
  color:#000;
• To change the width of the results, add to this definition:
  min-width:250px;

To change the individual items styling:

• Add to your template css a section for autocomple and add a definitiion for the class pac-item:
  .pac-item {
  }
  
  
• To change the color of the item, add to this definition:
  color:#CC0000;