Get some OSRAM or Philips W5W LEDs and code out the bulb checks. Don't get no-name ebay ones or any CANBUS compatible ones, you'll end up replacing them! If you have a set of 4300 K HIDs the 4000 K LEDs give a subtle contrast.
When I ordered the LED number plate lights the parts guy knew the connectors that were needed, you just unlock the connector, push the tab in on the metal pin and slide it out then pop into the new one.