[Jack_Leslie]

Shit, I found exactly what you're looking for, a new feature that was added in 0.3e, I had no idea it existed.

https://sampwiki.blast.hk/wiki/GetVehicleModelInfo
https://sampwiki.blast.hk/wiki/Vehicle_information_types

Quote:

VEHICLE_MODEL_INFO_SIZE // Vehicle size VEHICLE_MODEL_INFO_FRONTSEAT // Position of the front seat* VEHICLE_MODEL_INFO_REARSEAT // Position of the rear seat* VEHICLE_MODEL_INFO_PETROLCAP // Position of the fuel cap* VEHICLE_MODEL_INFO_WHEELSFRONT // Position of the front wheels* VEHICLE_MODEL_INFO_WHEELSREAR // Position of the rear wheels* VEHICLE_MODEL_INFO_WHEELSMID // Position of the middle wheels (applies to vehicles with 3 axes)* VEHICLE_MODEL_INFO_FRONT_BUMPER_Z // Height of the front bumper VEHICLE_MODEL_INFO_REAR_BUMPER_Z // Height of the rear bumper