
I just replaced mine first off go with the x-ring it's a little pricey but worth it (it helps retain the oil between the links better), and look for sprockets that are made of steel they might be a little heavier but they last in the end, I did the mistake of buying an alluminum sprocket and it was toast after 15k miles. I've heard of people getting less miles than that out of them. umm other than that it's just brand preference, I replaced mine with a D.I.D. 530 chain x-ring with steel parts unlimited steel sprockets 3k miles ago. Oh yea and the teeth are 15 front and 40 rear unless you want to go 2 up on the rear for more acceleration, but it'll throw your speedo and odometer off more so than it already may be (sport bikes tend to be 10% off reading high give or take a few %) unless you get a speedo healer. And that's all from me.