WAS VERY EASY TO INSTALL, AS ALL WOULD BE. SLIGHTLY DIFFERENT FROM STOCK, WHICH WAS A CONCERN, BUT A QUICK CALL TO RK CALMED MY FEARS. Only have 350 miles on the new sprockets and chain, so I can't attest to durability.
Gave 5 stars because easy install, good quality, and does what it says it will do. Anyone thinking of buying this will need to take note that this will decrease your mpg (decreased mine about 5 mpg, I ride hard) and you will need to adjust your speedometer accordingly. Again great product. If you are looking for a faster acceleration this is your product.
I've used several different 520's from RK and every time they break. Even the xso and gold series broke at master links. Some were clip type and some were rivit. either way I'm not impressed at all and will not buy this brand anymore.