I would change the oil to a premium synthetic such as Mobil 1 or Castrol. The oil weight should be what your owner's manual recommends. If you do have the owner's manual normal maintenance should be listed, otherwise do a search on the Internet. Using a good synthetic oil allows you to change oil and filter less frequently, say 5 to 10K miles. I change mine once per year unless I've done lots of city, stop and go driving. Nice car, glad you want to take care of it!