My 1996 XR400R has finally worn through the rear sprocket. I think I might have run it with too much slack. Anyway, it sounds like I should replace the front sprocket, rear sprocket and chain. I ride in the Colorado back-country, my skill level is intermediate at best. I want to maintain the OEM performance and durability. Should I buy the OEM replacement parts or are there better, more durable sprockets and chain? I don't mnd paying a little more to get the best quality. Thanks for your help!