I prefer they not have subgroup^^
i think the group that should has sub group is the group that has many members..like SNSD, After School (already have), Super Junior (already have too:)), 2PM, Nine Muses...
this is bcoz if group that has many members has sub group the unknown member will be get higher popularity:)
but if DSP consider KARA should has sub group,then as fans we should support them^^