To be honest I dont think it really matters, but I use regular oil. The last time I had my oil changed it had been 5,000 miles since the last one. I had it done at Grease Monkey and you know how they dab some of your oil on that piece of plexiglass and show it to you? Well mine looked like I had just put it in the car. And I am pretty damn hard on my car. I plan on changing my own oil from now on, so I will be going to a synthetic just because of the money I will be saving.