I was talking about carls 900 they’ve been building since the 850 came out. I only know of one I have built I sold it to a friend it has 2,000 miles with no issues. Not sure on durability of 9R I quit trying to run a sled past 1,000 miles.The only thing the 9R has proven is that it's here for a good time, not a long time. 9K in warranty work after 1800kms last year. I don't know anyone that rips with a high mileage virgin 9R...
Just from experience durability and performance rarely go together.