F350 with Host Yukon flat towing

A supplemental system is required by most states if you exceed 3000lbs or can stop the whole rig in a specific distance. That said you are nuts to have even a Miata pushing you down a mountain or into the back of a semi. Brake Buddy has a good state by state listing of regs. Once you have the brake system dialed in you should not even notice the car is there. All my trailers have brakes on all axles and with a 4wd tractor w/loader and box blade on my 22' I can dial em up so it feels like I dropped an anchor off the tailgate of my F250. I've crossed scales at a metal recycler just shy of 24K and as long as I had good brakes, no worries.