Gang Styles+

[-SeaboundSaint-]

Question: Which file do I use if I'm using both FPA+ and GOTR?

The FPA+ version, since FPA+ was built on GotR's files.

 

[HKSvsGreddy]

Juiced Patch (v7.1.0 or later):
1. COPY the desired "gang_customization.xtbl" file provided by this mod.
2. PASTE into the "mods" folder in your Saints Row 2 root directory (where SR2_pc.exe is located).
3. Launch Saints Row 2 and enjoy your new Gang Styles!

And based on this, there's no need to create a folder inside "mods" and add it into loose.txt to install it?.

 

[reina3]

And based on this, there's no need to create a folder inside "mods" and add it into loose.txt to install it?.

You can do that for better organization and knowing what files belong to what mod, but by default Juiced supports files in mods folder anyway.
It's because this is at the bottom of loose.txt:

mods

Though, you still need to watch out if other mods use the same files as this one (file conflicts).

 

[-SeaboundSaint-]

And based on this, there's no need to create a folder inside "mods" and add it into loose.txt to install it?.

Since this mod is just one file, it's not really necessary to give it it's own folder. You can if you want though.