if you have enough money and have the know how (or know somebody that does) then anything is possible, i've seen imports with corvette engines in them, saw a 350Z with a corvette engine
but it just wouldn't be worth it for a sunfire, honestly i'd take a sunfire engine over a honda engine anyways, i know i'll get thumbs down but oh well i don't care
what you should do is since you rather drive the sunfire and if you don't need 2 cars just sell the honda for what you can get for it and use that money for the sunfire engine rebuild or new engine, sucks since the honda has a new engine but that might be the only thing to do because it just wouldn't be worth it in my opinion to try to put a honda engine in a pontiac
im not sure what it would take exactly or how much money but im pretty sure it would take the same amount of money to swap the engine than it would take to just rebuild the sunfire engine or get a used engine