We put a sunnybrook in our 8820 and it was one of the biggest selling features when buying our 9610. It is absolutely worth it in my opinion. You don't get the vibration from dust on the back side of the bars, tough slugs go through much better, when it gets tough you will notice a big difference. The minus is installation they are HEAVY. You don't need the concave and cylinder if you don't want them. I wouldn't run without one. Get the boronized bars as well.