I've been trying to get some info one service intervals. I have 11 versa 1.8 6 speed. just went over 52,500 miles. I do oil changes every 4,000. I'm starting to get pretty serious about taking better care of it so I just did my first royal purple oil change. Man it runs a lot better now. Way smoother. Not sure if I've noticed a mpg gain. Have only been 200 miles. But thinking of doing a tuneup but not sure if it's ready or needed. I'd love your input.