Greetings Sir or Madam and welcome to JA! I will do my very best to assist you with your problem.
If your question is in regards XXXXX XXXXX then the normal is 5-W30. This is a good multi temp oil and is recommended by subaru.
If the question is whether or not you should be using synthetic oil.That is a personal choice.There are advantages to the synthetic,but the main one is it will last longer then organic, so you don't have to change the oil as often.
Hope this helps! Please reply if needed!