Hi Christain
If you want to add new search criteria , you can create a new field using AET . While creating you can make it as Search relevant or Search Result relevant field. So that the new field will also appear in search page node.
Also you can do search enhancements through BADI . But using AET it is very easy . If we go through BADI we need to handle the code . If we go through AET code will be already handled in the backend.
Regards
Dinesh Gurram
