1. i wouldn't run stock internals.
2. i'd go atleast 550cc's on the injectors.
3. tuning depends on how many headaches the tuner runs into while working on it. they usually charge by the hour.

go with h-beam rods, high silicon pistons, a good set or cams (something around a 280/280) and get a good set of valve springs.

then once you get the parts take it too a machine shop and completely rebuild it, have the head surfaced and the valves re-faced, and have every gasket/seal in the motor replaced.

do it the right way. don't just swap heads and slap a turbo on it.