Turbo six on a Budget

How hard it is to oring the block? I see there is a tool to do it yourself and is it worth it. like i said my hp goal is ~350 how much boost does that take?
Any and all machine work should be done by a machinist. Including oringing the deck. As to how much boost will it take? It depends on how much hp the engine makes NA and how efficient the entire hot side is, how efficient the charge cooling is, and how appropriately the turbo is sized for the engine. Way too many variables to guess at a boost number.