Review on 🔥 NGK (4548) CR9EK Spark Plug - Pack of 4: High-quality Performance and Value by Karthikeyan Behm

I used these hotter connectors (instead of the factory recommended CR10EKs) in my 2003 R6. Where I've had trouble breaking past 14,000 rpm, they run smoothly throughout the rev range and are much better suited to older R6 engines, especially high mileage ones. Can't comment on durability as these are just plain old copper plugs, but they will definitely last quite a while, even compared to equivalent iridium plugs. Highly recommended for first and second generation R6 (or R6S) but I would stick to the recommended heat range for all new bikes. They are quite expensive for a copper connector, but still work as expected.