With the way you'll be tuning you should notice a nice increase in output.
Technically because your filter should be set around 30-32hz you wont be able to play the super low notes you would with a sealed box. Since you can't really hear much lower than 20hz and almost no music has anything that low anyway, the music you do listen to will sound like it has more lows.
since the sealed box is on the small side you probably couldnt hit the lows very well if at all anyway but it was probably pretty tight on what it did play...when you port it it will probably be louder but it wont sound anywhere near as tight as the sealed box was
