Diff Dilemna! Need opinions!

As was said, they rate them at 600hp but I've never heard of soemone breaking one. I've got a few behind real 500hp engines with no troubles. They are a gear type... I've never had one that needed service so honestly I don't know if you rebuild them...lol. I would still put shocks in it but that's me. I also ran the solid bushings on my Cuda years ago. I replaced them with poly and it was 100% better. The solid bushings are not fun.