Hello Eduardo,
1. You can delete the src files but not the folder or the index.html file in order to save up some space.
2. I would not hack the core in your position, it could lead to unexpected results. I think with just deleting the src files you will have saved enough space.
3. If you hack the core you will lose your changes in the next update as well.
PS. Always backup first
JoomlaWorks Support Team
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