Grunfeld rook sac

I just was playing an OTB game and I saw a blunder and exploited it even after blundering off a rook.

Brilliant comeback there! You must have freaked your opponent out.

nice ....

Almost never a good idea to give up that bishop so early in the game in a Grunfeld or King's Indian.

Had I been Black I, too, would have grabbed the rook, but then would NOT have castled. So I'm wondering if I get into that position, can I hold on? With good play on both sides can Black turn the material advantage into a win? I'm thinking f6 to block the diagonal, Nc6 to block White's passed pawn, a6 to defend b5, maybe Be6 or later Bf7, O-O and Black has a pretty good position. Then maybe double the rooks on the open d-file. I think Bxa1 was a good move even at the cost of an important bishop; the blunder was O-O.