I only know one person who had an issue and it was the stock input hub that failed not the shaft. It was a 3,000 lb car that ran 8.80s-8.90s @ 150+. It was trans brake as well. But other than that, I have never heard of anyone having one fail. I know plenty who have ran high 8s-low 9s with heavy cars running stock input and output shaft. To include DVW.

I know if you were to do one or the other I’d say do the input and the hub. But I personally would do the roller components first. Just my own opinion.