The Game Boy Advance of Final Fantasy V featued a terrible port of the music, with aggressive instruments. This hack was made to fix this problem by re-inserting back the original SNES soundtrack in the GBA game.
In this version 2.0, the Final Fantasy V Advance Sound Restoration hack has been completely remade from scratch in a new version, using the same technique used in the Final Fantasy VI advance patch, where the soundtrack was entirely re-sequenced.
The hack also changes a few sound effects, and features a fully orchestrated introduction !
As a plus, this hack also greatly reduces lagging problems that were introduced by reducing the CPU usage for mixing sound. Now all spells will play their animations at the original SNES rate.
RHDN Project Page
Relevant Link: (http://www.romhacking.net/hacks/563/)