I went 2 up on the rear and converted the 532 to a 520. It made a nice difference on the bottom end because of the combination of less rotating mass and slightly larger rear sprocket. I went with a RK x-ring chain and AFAM sprockets. You will love the acceleration and not lose too much top end.
Originally posted by ssg_mac so you dont have to change the front one??
no you don't have to although some do go to a smaller front sprocket for the same type of gains in acceleration and bottom end but the chain can suffer more as well. If your looking for really big difference then changing both (adding 2 or more to the rear & dropping a tooth or 2 from the front) will get you there. I should add that if you do the conversion from a 532 down to the 520 then you will change out both sprockets. I kept the original tooth count on the front and went with the 2+ on the rear. I really like the difference.