Enclosed car hauler...
I agree on the axle upgrade,3500 lb axles just aren't enough. That only gives you a towing capacity of 7k Including the weight of the trailer! I have traveled to other states with friends pulling cars with 3500 lb axles and it seems like they always carried 2-3 spare tires. And some times needed them all! If I were to upgrade only one thing on a basic trailer, it would be the axles.