ArcSDE is the best option to Import and Manage your Geodatabase in Database servers ( SQL server,Oracle ,...) . You can't import File Geodatabase or Personal Geodatabase directly in SQL server . you should use ArcSDE software . The Geodatabase type of ArcSDE is SDE Geodatabase not File Geodatabse. I think you should use ArcSDE to Import And Manage your Geodatabase. Don't think aboutdoubt to change of Geodatabase type from File to SDE Geodatabase. maybe you'd like to use Permissions,Versioning,History,syncronizing and another capabilities of SDE Geodatabase.