Form editor - Case

We would like to amend the Main Case System Forms.  We want to delete certain Tabs/Sections but these seem to be locked (red padlock).  I also want to add Sections, in particular, I want to display any documents that are related to that Case in the Case Window so you do not have to hit the arrow key and select if from the Common drop down.

From what I understand these locked areas are linked to other elements and are needed in order to allow the system to operate correctly.

I understand these can be hidden from the users view but will always show in the form.

Would my best bet be to create a new unmanaged solution and input all the required fields that are needed? 

I have search on how to do this but haven't find anything.  Can someone point me in the right direction?