This is the file that switches Families's cars to red & Ballas's cars to blue.

This file goes here: E:\Games\Rockstar Games\Grand Theft Auto V\mods\update\update.rpf\common\data\ai
The reason I didn't include it in the OIV package is because some people might have a different vehiclemodelsets.meta and I didn't want to screw it up. If you're one of those people who happen to already have a modified version of vehiclemodelsets.meta open the one I provided and search for LOWRIDERS_MODDED_BALLAS & LOWRIDERS_MODDED_FAMILY and copy and paste the lines under LOWRIDERS_MODDED_BALLAS & LOWRIDERS_MODDED_FAMILY to your current .meta!