GTAV Can Los Santos Customs mods be edited/modded?

[TheOriginalEvilD]

I've searched everywhere for this but I'm new to modding this game (though I have modded the handling files of every GTA prior to V). What I'd like to do is, instead of modding the handling file and having every car that spawns in the game having modded handling, I'd like to be able to mod the Los Santos Customs mods so that I can make my own car faster through those mods. In other words, I want the turbo mod at LSC to give me a lot more speed than it does, the engine mod to give more horsepower, brakes to give better braking power, etc. All I can seem to find are complete handling overhaul mods or a slew of drifting mods. Is this even possible?