PCHicks

I know you won't want to do this. 
But its one of those or multiple plugins that haven't been updated for compatibility with the latest  RPH.
You will have to go thru and put one in at a time and do the same method thats causing the crash. Do it until it crashes with the same problem(s) you've mentioned.
It will take a while.
Also you can post your RPH log and maybe someone thats good at reading those can tell you EXACTLY what the issue is.
I feel your pain man. Good luck.

It's probably because the vehicle models you downloaded have low quality, GTA (like nearly every other game) is using a system (LOD) where a model displays lower quality models of itself when you get further away from it.
The wheels disappearing means that the guy who made the model didn't bothered to also make lower quality versions for it. Models lacking this feature are also known to cause perofrmance issues, that's a problem.
There is a easy way to verify if a model uses this system, just open the normal .yft file (not the one with _hi at the end) with OpenIV and do this. (image by Sniper296)
Well it could also be caused by some vehicles.meta stuff, but I don't know too much about this things...

Probably the lods are not setup is why

Try different models. None of the cars I have have this issue. Also, make sure you install any .meta files that come with the vehicles. 

It's ok I have sorted it. I did what you said and edited the INI and all is sweet. Thanks for taking the time to help me out.

In the INI for Arrest Manager you can choose which vehicles to use for pickup.