I have finished editing the levels of my hack and yesterday I edited the sound_data you can try it in VGMTrans and tell me what do you think or give me some suggestions?
http://www.mediafire.com/?giy91cqzr5ze8bb

Hi, i'm SpongeTown!
I've playing Mario Bros. with your sound_data.
It was fun! I like the changed Dessert-music!
I've got maybe great ideas for musics in your game:

BOSS MUSIC --> Mario Party - Boss Music (http://youtu.be/Q3lhLp3Gsr0)
WORLD 1 MAP --> Mario Party - Wiggler's Garden Pest (http://youtu.be/-vweALgGIBg)
STARMAN --> Mario Kart DS - Starman (http://youtu.be/saPduhUBkQE)
UNDERGROUND --> Super Mario 64 DS - Cave Dungeon (http://youtu.be/JAKUriqFl5I)

Greetings, SpongeTown!