You can still search for other models, even though they aren't in the dropdown list. To do so, set the drop down to "Other ___ Model", (Where ___ is the make name, like Ford or Mazda). Then the dropdown will change to a text box where you can type in the model you're searching for.
If we're missing a common model though, or there's something else wrong in the list (wrong name, duplicate, etc.) please do let us know!