ok, got ya
the point is that in order to resize the data partition you have to
1.) shrink reader partition which is a primary partition at the _end_ of the disk
2.) enlarge extended partion which is the third partition of the disk
3.) move system partition to the end of the extended partition
4.) enlarge data partition
so you're right - no backups / restoring necessary, as long as your partition tool is able to resize / move the stuff around