Stock is 13/40
Less teeth in the front and more in the rear gears it lower. That does not necessarily mean better acceleration, in most cases it's actually going to slow your accelation because you're running out the gears quicker and spending more time shifting and less time on the throttle. I tried lower gearing (12/40) when I got mine because everybody was saying it was great, I absolutely hated it and switched to 14/40 and seemed like it was as good in acceleration as stock and pulled all the way to top speed without running out of gear. Sometimes people get the impression that the lower gearing is making it faster, it might just create the illusion of being faster because it's revving quicker and shifting quicker, in reality you're just spinning the tires more and shifting more often.