Well, if u have the proper brakes on the trailer, it wont matter whats on the truck. The trailer brakes are supposed to be capable of stopping the entire trailer weight without any additional braking effort from the towing vehicle. The truck brakes only need to be able to stop the truck.
If the trailer doesn't have adequate brakes, it wont matter what's on the truck, cuz your're screwed.
Plastic trucks suck...
Iron trucks rule...