Hi Australia, you do not need to register (residency permit) unless you intend to stay more than 180 days - indeed you're not allowed to. You will find that most visas - even a year's one will be stamped with 180 max stay at one time. You do not have to be a resident to rent an apartment/villa. Anyone has any more queries on Goa and the current laws (they seem to change them every week) I will help if I can.