Whatever issue you are having isn't reflecting on the quality of the GNR100 mod, but your computer system. Which if you ask me is going above an beyond what any normal modder would do. Which it even goes into great detail on how to replicate the exact process the author used.
If you read the read me you would know that. Heh, The songs it contains are already matched to the volume level of the vanilla songs. I hope you know that in the in-game settings there is a slider for just the radio music.
