So im a fairly new mountain biker, like a year and half or so and my bike is now needing all new parts. Its a K2 ZED 4.0 and im replacing the cassette, chain and probably the crankshaft. I was going to get a shimano dura ace cs7700 cassette and chain but i was wondering if there were any better products out there. Also does it matter what type such as 11-21t or 11-23t ect i use. Any help on the matter would be great. Thanks