Hi I am wanting to make some layout changes to the Magento admin panel including removing the Sales modules from the dashboard, example: http://puu.sh/kpUkL/3398735630.png
I would also like to make some internal changes to the way that users add products to the admin. For example I will be adding an automatic product specification system that will fill in some fields depending on the SKU that is entered.
I am confident on making these changes however I do question what might happen if I where to upgrade Magento in the future? Would I have to go back and make these changes all over again or can you code these changes for future updates?