I'm planning to buy the ASUS AC66U AC1750 Router since I really do not like the ActionTec router that was provided by FiOS. I will set up using the guide that DSLReports.com provides:http://www.dslreports.com/faq/12506 . However, I have one question that I would like to ask before I purchase this router. I have FiOS TV and Internet. Will I lose my FiOS TV service I follow this guide? Or do I have to do something else in order to use the ASUS router and have TV service?
The TV service will be uninterrupted without the ActionTec in place. Just be sure you can get network connectivity to the ActionTec however, as it delivers Guide and Video on Demand information to the Set Top boxes from Verizon via MoCa.
See this page for more info on how you could go about doing this: https://secure.dslreports.com/faq/16077
Will I lose my FiOS TV service I follow this guide?
If you follow the link you quoted, you will not lose FIOS-TV service. However, that link turns your router into a wireless access point (WAP) and a switch. The WAN features of your router will not be used. The Actiontec will stil be your primary router.
There are a number of other options listed in the link that smith6612 provided.
By WAN features, do you mean like dualband and 802.11ac?
No. Those are wireless features.
WAN features include port forwarding, firewall, DNS and routing.