Welcome, Kyoudai.

The purpose of this guide is to tell you how to install the Classic Music Mod mod for Yakuza Kiwami meant to restore the music from original PS2 release of Yakuza 1.
Yakuza Kiwami remixed all music, arguably for the worse, without offering an option to choose original PS2 soundtrack.
This mod does just that, it replaces the remixed music from Kiwami with original PS2 tracks from Yakuza 1.
In few rare instances where certain tracks didn't exist in PS2 Yakuza 1 (Lau Ka Long's theme, Amon's theme) we have used their equivalent variants from Yakuza 3 which are the origins of Lau's and Amon's unique themes that Kiwami remixed.
All the tracks are naturally properly looped, with 1/1000 of a second precision for seamless loops and transitions.
Volume levels are likewise normalized to be as close as possible to Kiwami's volume levels so that they aren't jarring.
The mod also restores the proper placement of "Intelligence for Violence" in the Nishikiyama Clan fights in front of Serena and during the long battle leading up to Arase, just the way it was back on PS2.
Furthermore, the mod includes Yakuza Kiwami Licensed Music Restoration Patch as it doesn't interfere with the PS2 music in any way whatsoever, so you do not need to install it separately.
Feel free to read the separate guide for the Licensed Music Restoration Patch below for more information.
https://steamproxy-script.pipiskins.com/sharedfiles/filedetails/?id=1660892640
Those of you that might be familiar with our music restoration patches for the PS3 and PS4 Yakuza titles should be right at home with this guide, as the steps to follow will be just as simple if not simpler thanks to not needing a hacked PS3 or PS4 console to use this.
This video below will give you a glimpse of what you can expect after restoring the licensed music, it comes from the PS4 version of our mod so there might be minor differences in menus and logos in the video, but the general principle regarding the music and how it's placed is exactly the same.
A word of warning, the video contains SPOILERS for the main story.

Now here come the steps on how to install the mod.

First of all, you will need to download the package from the link below which contains the patch and all its necessary files:
https://www.nexusmods.com/yakuzakiwami/mods/35/

After that, extract the contents of the archive with the patch to a folder of your own choice, it's compressed in 7z format which can be unpacked using 7zip or WinRAR, though I do recommend 7zip for best compatibility to avoid any potential issues.

Next you'll need to open the folder with the game itself, naturally make sure it's installed beforehand.
You can do so by Right Clicking it in your Steam Library and then selecting Properties -> go into the Local Files tab -> and finally press the Browse Local Files button which will open the folder with the game.

If you're playing the game in English:
Now all you will need to do is select all the files from this Classic Music Mod and copy them to the folder with the game, overwriting the files when asked if you want to do so - this is crucial.

If you're playing the game in Japanese:
First, before copying any files you will need to rename the "movie_w64_e" folder found inside the mod files to "movie_w64_j".
Then you will need to do is select all the files from this Classic Music Mod and copy them to the folder with the game, overwriting the files when asked if you want to do so - this is crucial.
Finally, you will also need to copy the contents of "Only For Japanese Language Version" folder and copy them to the folder with the game, overwriting the files when asked if you want to do so - again, this is crucial.

The only thing left for you at this point is to simply start the game and enjoy it in all its restored glory.
You can expect similar guides for future Yakuza games once they make their way to PC in the future.

Welcome, Kiryu-chan! So, did I get ya pumped up!?

I would also like to direct your attention to the upcoming Yakuza Kenzan fantranslation project being worked on by my friend, Slow, you can find more information about it as well as my patches for the PS3 and PS4 Yakuza titles over on his website which can you find under the link below:
http://yakuzapatch.tumblr.com/