T56 tranny with an 8.8 rear end should handle the power.

 

You’re going down an expensive rabbit hole. Some of us have pushed beyond 800hp, but cheap and reliable don’t ever really go together. For starters you’ll need bigger injectors, fuel pump, and fuel lines. You’ll also need a bigger turbo. You’ll also want to upgrade springs, valves, retainers,etc in the head. Then you have to worry about the drivetrain. On top of that you’ll need an ems, not sure what you’re using now. Then you want to add sensors so you can monitor some of the things going on while pushing 30+ psi of boost

 

The engine is not the problem at your power goal, the drivetrain is. All you should have to do to the engine is inlinepro m12 head studs and maybe valve springs, thats it. The trans and diff will not take that power for very long though, so you'll need to swap both, plus a new driveshaft and axles. You'll need much bigger injectors and fuel pump too.