So I want to know what you all think. I bought my bike from a friend who passed away. It's got high end quality parts but it has a couple issues. The rear sprocket is one of the Renthal aluminum sprockets with steel teeth. But the chain is a cheap gold race chain. Every ride the chain is stretching out quite a bit and it needs to be replaced. The sprockets are still good but do show a little wear. My question is, would I go ahead and get a good o-ring or x-ring chain now or get a complete kit with chain and sprockets? All new? Or just one piece?