The default format for export format for ArcGIS 10.1 is DWG_2010. Is there any way to change it to another format? In my case I need it to DXF_2000. The only known way to export to cad for me is right click on the geodatabase -> data -> export to cad.
Via the ArcGIS CAD export tool interface, the default is the latest release of AutoCAD supported by the ArcGIS version you used to export. Can't make a preferred option stick. With a script or model builder, your output options are permanent, unless changed and therefore preferred option can be made to stick.
From the Help file for this tool, you need only change the parameter Output_Type to DXF_R2000.