its not about how much weight a vehicle can pull. a lot of cars can pull way over the rated weights, its about safety. If you have it loaded down are you going to be able to turn or will the front end be so light because of the load on the back that it hesitates a little. Also braking....just cause something can pull 5k lbs doesnt mean it can stop it safely. I've pull trailers from 500-20,000 with light weight trucks 1/2-1tons and you begin knowing the limits fast. If i were to buy a vehicle intended to pull 5k lbs (a car per say) i wouldn't buy anything less of a 1/2 truck.