Features and Implementation Status
1. All Vehicle Trunk Space Changed - Implemented
Generally buffed/rebalanced all Vehicle Trunk Sizes.
Vehicles that you would expect have a lot more space, Trucks get up to ~45, Vans up to ~60, and most cars are from 3-20ish.
2. All Vehicle Tank Size and Fuel Efficiencies Changed - Implemented
Vehicles hold gallons of gas, Small Tanks hold 12 gallons, Basic Tanks hold 18 gallons, Large Tanks hold 24 gallons and Massive Tanks hold 48 gallons. Fuel efficiency was calculated to be somewhat realistic but is balanced as to not vary too much. Vehicles won't run out of gas as fast because they have more capacity but it will take longer to fuel them up. A second pass will need to be done on this which will included assigning more specific tank/efficiency rates to all the vehicles.
3. Slightly buffed all vehicle damage/health - Implemented
A second pass will likely need to go into this one, some vehicles may get significant buffs and others may become more easily damaged depending on what they are made of and what kind of vehicle they are, but generally most of the vehicles received a slight buff.
4. Change Vehicle Availability and Trunk Loot - PLANNING
5. Remove the call in's for overpowered vehicles and create a new way for players to earn them - IDEA/PLANNING

Note: Realism and Balance was heavily considered in this mod but likely I will have to make a few passes to perfect it.

Here is a somewhat accurate list of the trunk adjustments:
Upgraded Vehicle with Fuel Tank instead of a Trunk - 1
Muscle Car - 3
Sports Car - 5
Sedan 1 - 7
Sedan 2 - 9
Hatchback - 15
SUV - 24
Jeep - 24
Small Truck - 33
Passenger Van - 42
Large Truck - 51
Cargo Van - 60