Tech Ping!! Help Please? Nighthawk X8 8500 died. Need to replace with similar router. This is a big one with 4 antenna. Works in big house with three floors. Please Help?

Tech Ping!! Help Please? Nighthawk X8 8500 died. Need to replace with similar router. This is a big one with 4 antenna. Works in big house with three floors. 75 foot length. This one has covered the whole house well. I need to find its newer younger brother. Is there a router expert here? Please Help?