I drive an 03 2.5s with 18000 miles on it I have owned it for a little over a month now. I was wondering what is the type of motor oil 5w30 or 10w30. Also is it better to run like Castrol GTX or any other name brand. Question number 2 the lifters or fuel injectors seem to be a little noises is this the case for all 2.5s. My last car was a 01 sentra se 2.0 and the motor in that car was always a bit on the noisy. Thanks for your responses.