I'd give the same answer but note that WiFi is a shared resource. Those that have been around the block understand that we wire what we can to preserve our WiFi bandwidth. AC does not solve this!
I rent a modem TC8305C from Comcast and use my ASUS RT-N56U router. I pay for "Blast" service. I want to buy a modem and return TC8305C to Comcast. Questions: Which modem shall I buy and do I need to replace my router? It was suggested that I get a SB6141 modem and a router with 802.11ac protocol since I use several devices with Wi-Fi particularly Video Streaming such as Netflix with AppleTV. Your recommendation will be appreciated.