In the rear: the more teeth you add, the faster you will accelerate. A very common change is +2 teeth in the rear for a total of 48.
In the front: The less teeth you have the faster you will accel. -1 tooth is very common. wouldnt go less.
I had the -1 in front and loved it. Just recently put on the +2 in the rear also. Only been down the road once. But its a wheelie monster even more now. Probably going to be good for the track.