Carmageddon, pretty much exactly the same as it was in IV, considering I did it the same way.
Cars go nuts, flip around, explode, you know.
Sometimes the front wheels fall off which leads to half-hearted doughnuts, such as in the screenshot.

To install:
Using OpenIV, take handling.meta and override the original located in GTA V > update > update.rpf > common > data

Known Issues:
Some cars aren't affected. Seems to only be DLC cars that I haven't touched because I'm a lazy asshole, but I might have missed one or two in the base game.
I don't think I saw any motorcycles affected, which would be in line with how it was in GTAIV.
Cars may deform more than usual, I might have used my personally modified handling.meta for this. You probably won't notice anyway, and I probably won't fix it (because I'm a lazy asshole).
Not really an issue on my end, but cars are less packed in on the street here than they were in IV, which means this is considerably less fun. I'm sure a mod that increases traffic would remedy that.

In case you are wondering, the fly shirt Trevor is wearing was created by ZiPPO RAID, https://www.gta5-hub.com/player/old-vietnam-fatigues-for-trevor