No engine is MADE to handle boost that didn't come with it from the factory.

That being said, GM improved some engines over time that were capable of handling a good amount of boost with little to know mods, IE, 5.3L LSX, N/A 3800, etc.

I persoanally would not get a 3.9, because it hasn't been around long enough to be improved upon or build a reputation based on reliability. If you're a gamer, think of it like the original xbox 360, they all had problems, most didn't happen right away. Then the second edition came out and they are much better.