So some things I've learned about cars:
They are quite easy to flip and once they flip the little hand icon kick thing doesn't really do anything. Luckily when I did I didn't have tradepacks on board.
Small cute pets can ride along if you stand on the hood and summon them at the seats.
The trash in the street in Marianople can flip / crash/ get you stuck.
Driving underwater is really strange. Sometimes you blast along full speed, and sometimes you crawl at a snails pace. I'm not sure what causes the different behaviours.
On streams I've seen other people's cars begin to smoke and they had to use this coolant on them. I drove alot last night and this morning and that never happened to me so I have no idea what causes it.
When assholes block bridges with carts I can just plow right through them. I think this is because my 1.5 mbit dsl just can't keep up with the speed of the car, so like I can drive by housing areas with the houses struggling to load up and appear.
You can't jump the broken bridges. Maybe in the coupe, as it has some kind of jump ability.
The car does not slow down with tradepacks on board. Or if it does it is like .1 or something. I couldn't tell.
I think the cruising speed is about 15 meters per second or 33mph.