I'm probably the biggest fan of running the factory computer left around here.
I have personally seen the factory computer work fine with 60's no tune at 650rwhp.
I've heard of guys going to 700rwhp.
But to put it bluntly, nothing in your plan is sensible, including using the stock computer.
Not the stock computer, the x cam, stock block, boost a pump, the heads, pretty much nothing.
You are going to have to dial back that goal by about 50% if you want any shot in hell of it living past a dyno run.
You are going to need another $20,000 (at least) to hit 800rwhp.
Let me guess, the trans is a t5?
I'm going to save you some time and a hell of a lot of money.
Buy a
vortech S trim, set your goal to 450rwhp and go from there.
Anything thing else is just a pipe dream for a guy on a budget.