Is this a replace model or an addon? Is the vehicle installed into a proper patchday and also named sheriff or sheriff2? If it is just a replacement, you can just copy over your original vehicle.meta file and start fresh, safer that way. Shouldn't really need to make changes to be honest. However, the handling ID, would need to be changed to police2 or buffalo would work. That's all you really need to change, unless you want to add audiohashes for a better engine sound.