The stock plastic guide/guard will be fine. I've run a 525 chain for a couple of years now with no issues in this respect.

The most common cause for problems with the swingarm guard is when the shock is saggy, lowering links are fitted and/or the bike is heavily loaded (regardless of chain type). In this condition the swingarm sits in a horizontal plane and the chain makes continual contact on the forward lower edge. There have been a few instances where the guard has worn through and the chain has eaten through the swingarm down to the bearings!

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