Is there a space-effective way to insert MP3s?

I'm making a multiplayer battle.net movie making map. I want to be able to have MP3's for different moods in the movies that people make. I used some from Blizzard, like the pursuit theme, tension theme, and sad mystery theme, but the rest just don't cut the mustard.

Is there any way to insert MP3s and keep the map from lagging like a turkey?

Firstly turkeys lag?
Secondly, it won't lag, but the file size will be increased, wich means Dling the map will take 3 or 4 + times as long. Wih is just to much for a Bnet game. :)

Turkeys can't afford cable.

Ooh, is there a way to make MP3 files smaller and still be able to get em in warcraft? Is there a way to remove the warcraft default music files I don't want to make room?

Hoorah! I've killed the forum! Next stop, THE WORLD!