@Itsricana55a551n
Dude, just open the gameconfig file and you will see everything ... there are traffic values like on cars who are parking ... cars who are driving ... also specific cars like country cars, poor cars, more rich cars etc ... so you can change mostly everything.

then there are also amounts of cars you can use ...

here is the site, what explains you bit more about what you should change in gameconfig if the gameconfigs here doesn't work:

https://gtaforums.com/topic/827458-addon-car-issue-maximum-reached/

as a tipp, make everywhere x20 or x50 times more :D

like that for example:
<PoolName>Vehicles</PoolName>
<PoolSize value="400"/>
<PoolName>VehicleStreamRequest</PoolName>
<PoolSize value="145"/>
<PoolName>VehicleStreamRender</PoolName>
<PoolSize value="135"/>
<PoolName>VehicleStruct</PoolName>
<PoolSize value="300"/>
<PoolName>HandlingData</PoolName>
<PoolSize value="780"/>
<PedsForVehicles_Base value="175"/>
<PedsForVehicles value="175"/>
<VehicleMemoryMultiplier value="600"/>
<VehicleUpperLimit_Base value="140"/>
<VehicleUpperLimit value="230"/>
<VehicleParkedUpperLimit_Base value="60"/>
<MaxVehicleModelInfos value="410"/>
<MaxExtraVehicleModelInfos value="200"/>

but now higher ^^ its still old what he did ... i did 40 times more of that :D

and here:

Since last update you need to increase "FragmenStore" value too in gameconfig.xml , put 10 000

also put it higher ;)

But note!! i don't take risk if your graphic card will have a crash of gpu or your ram is crash of too much stuff inside.

cause i have 60gb as mods ;)

that mean you need very much ram at least ... if you do add ons.

and if you make replaces, you need also more gpu like 8gb is the minimum.

with a gtx 970 only 4gb you cant replace all cars .. just 100-200 replaces then its enough you cant handle more, it depends how big each car replace is.

normally like addon ... 1 car can be 100mb :D so 10 cars = 1gb :D 100 cars can be about 10gb ^^

so have 100 cars at same time on your screen = crash when you have 10 gb and only 8 gb .. too much for your graphic cards.

one more tipp, you can set more graphic gpu in your ram :D but it takes some milliseconds then :D

but dont do one thing ... dont do ram fix with your ssd :D so if you dont have ram, just buy more ram :)

if its still not work, i can send you my gameconfig, but like i told you, i don't take the risk, that your computer will overheat or getting out of order for my settings :D

another tipp is if you really wanna do 1000 files, and have maybe problem with dlclist .. make packages ..

like alfa pack
bmw pack
bugatti pack

etc :D so at least you have just 50-60 dlscs insteat of 1000 dlcs in the dlclist and the dlcpacks folder :D

if you dont know how to do, then figure it out :) also how to change gameconfig and what each parameter or line is doing :) its "gold" ;) at least when you always know what to do and where the problem if something happen or crash.