42 Fountain with 525's and ITS-XR drives. Cruising around 3500 rpm and throttling into it. From what I have read, this is the rpm where things break. What is the best "fix"? Add better propshafts or go back stock and just be aware of the rpm range? Also, do you guys think the upper case can be fixed?

Buy the max worx billet shafts,they have different options,the only thing is you have to do a little bevel on the gear where the shaft meets it because the splines are rolled up with a fillet there (which is a GOOD thing). They have a insane shaft for guys running insane hp too but unless your running 1200 hp and 5 blades I think it's un-neccesary. There material has a torsion affect too with what they call a "memory",Smitty