Performance upgrades from 500hp up to 1500hp

If anyone has any questions about what kind of upgrades they can do to reach a certain power amount or for a specific use please feel free to ask, ive done many diesel projects, the most recent was on a 1992 freightliner fld120 with a 460hp n14, I did a turbo swap from an ht60 to a borg warner sx500 compounded to a sx400 both non wastegated, I sent in the injector nozzles to confederate diesel and had them honed +50% over to compensate for going from 30psi of boost to 56psi boost, I use twin turbonetics 45mm mechanical wastegates, I am running adaptronic programmable ecm and software, the n14 engines can only handle about 750hp and roughly 2400 pounds of torque before the block and crank start to crack. at 56psi I'm making 756hp and 2488 torque with peak torque at just 900rpm. I dropped the wastegate from 50psi to 45 with overboost of 6 from 50 I'm hoping it will be right at 50 and put me back in the safe zone also running banks double shot with 625 nozzles. trucks is just a sled pull project at the moment. cat 6nz can handle about 800 with stock #57 injectors and stock turbo's and roughly 1000 with stock turbo's and #59 injectors, block and rotating assembly itself can handle roughly 2000 before needing custom rotating assembly, if anyone has any questions about anything just let me know, I have the knowledge to get you about anywhere as long as you got deep enough pockets for performance parts.