There isn't much that is easy to find out there. Apart from Xposed installer and Wanam exposed which is OK to alter stuff like the notification bar icons and colours it is not as easy as 3minit framework, which I might try to see what happens if I use an SGS4 version. (I feel it will just not work or soft brick - I need to flash a deodexed stock ROM to even try, not for now)
So far one small flashable .zip that works on a stock (still odexed) rooted ROM is a volume increaser :
Moderate is best to my ears, loud distorts and is probably not so good for the speaker doing the distorting and possibly the phones inbuilt amplifier.
[MOD] Volume Boosting Sound Hack Mod | For Galaxy Note 3 | ONLY SNAPDRAGON VERSION !! - xda-developers