The real question is how deep are your pockets?
your prob looking at 15k as a minimum to get it high 400's. people will say that's silly money, you can get it cheaper etc etc, but you find cheap tends to mean compromising and then reliability becomes an issue. List of parts soon adds up,
Block (closed deck 2,5 would be my choice), Crank, Pistons, rods, heads, Turbo, ECU, injectors, fuel pump, map sensor, boost solenoid, Gearbox, Diffs, cooling (oil cooler), induction, intercooler, brakes etc etc etc
You need to look at everything