You do use factory track to mount the cover rails into. It can accommodate factory tie-downs, but you get a little restricted on movement, since the cover brackets break up full track movement.
Still liking the Lomax. Put seal around tailgate to keep dust and water out. No problems at all with water and it has been through downpours and carwash a few times.
Just installed a Lomax (not the Stance). Ordered from Real Truck and it took two weeks from order to delivery. Impressed with the engineering, fit and finish. I see grumblings about them leaking and I guess time will tell, but I’m super happy with it. Love the sturdiness and low profile.