Vehicle functions/hooks?

Are there any functions/hooks for vehicle entities?
Is it possible to make scripted vehicles? Using the prebuilt source vehicle system?

I’m assuming no, since it’s not on the wiki, but I’m going to ask anyway.

altering the script file for it is the only way afaik, I am sure azu made a module to editing a vehicle’s existing script after its already been made but I cant remember what it was called.

gm_pimpmyride