I believe adding a bit move variety of cars to the game would be a great addition! I have seen another server use the amount of dmg which an item has define the skin of it, aka letting ALOT more cars be added, just for the skinning, for example 1 dmg on a diamond hoe and it's a SUV and 2 dmg to the item it's another colour or whatever, but yeah, main Idea is just more cars, the rest is of course up to the developers, what's easier to them. (The server I saw it on is called Vindex, it's a city server with a ton of good looking cars, I don't know but you might try and ask how they do it.)
I hope you enjoy reading through the next suggestions coming after this.
Your beloved Boris_RW aka Surr