I have nearly 17k miles on my 2004 Zx10 now and it is time for a new chain and sprockets. I have heard its best to replace both sprockets and chain all at the same time. What is the best bang for the buck chain and sprocket combo. I have a -2 down front sprocket and a stock rear, I think I like this gearing. What brand you guys use Vortex? what kinda chain DNd? Is o-ring chain better or xring? :dontknow:520 kit or 530 for heavier duty use? thanks for any help and post me a link or 2 to some good sights to purchase from, I'll check w/our sponsors too!