i think any horn sounds better than the stock one. my vibe uses the same wimpy horns as your car and when i honked at someone that cut me off i actually laughed out loud lol it was so embarassing. it sounded more like "umm excuse me, can you move over a bit please?" lol i bought a horn from autozone and it sounded a lot better
but yah the horn's not hard to find...it's behind the grill and it's this small black disc thing...mine was pretty easy to install since it had a relay built in to the horn.