Minnesota Subie

Greetings Fellow Subaru Owners/Enthusiasts: I just took delivery of my brand new 2005 2.5L Ouback Wagon. Wow!!! What a car!! I love it!! My questions/comments: 1.) Can I change my own oil without voiding my warranty? If so, how can I prove that I did? Everything is so accessible on the Boxer Engine, especially with the higher ground clearance!! Changing oil looks like it would be a piece of cake. 2.) I put very few miles (5,000/year or less) on my cars.....a lot of short trips, so I'd like to change my oil more often than the manual recommends. I kept my last car for 14 years. 3.) How do you feel about synthetic oils? Are they supposed to make the engine run cleaner and is it true that you can go longer between oil changes? 4.) Any tips for changing your own oil? Does the oil pump (through the dipstick opening) method work? I read on another website that this method doesn't work on Subarus, but it doesn't say which years/models. What's the best kind of receptacle to drain your oil into and where do you bring the old oil for recycling? 5.) What about aftermarket oil filters? Are they okay to use? Which ones do you recommend? I was told that Amsoil oil and oil filters are the best. Any other tips, suggestions, etc. would be most appreciated. Thanks much. Minnesota Subie