God knows you can spend fortunes of cash on mods for your bike but none will be as effective in terms of bangs for bucks as a new sprocket and chain kit. In fact, if your bike is still fairly new or you've looked after the chain well, all you'll need is a new rear sprocket.
We've just taken delivery of a Afam chain and sprocket kit for our track R1 and will be fitting them before the bike's next outing. We were put on to Afam by the mechanics at Crescent Suzuki, who know a thing or two about fettling bikes. 
Afam is, curiously, a Franco-Japanese outfit with more than 25 years in the sprocket manufacturing business and, from what we gather, it's a damn sight more complicated than you think. In short – not all sprockets are the same. But if Crescent trusts Afam on their BSB superbikes, we can trust them on our bike as well.