NetBEUI on small LAN

I have a peer-to-peer, mixed network of Windows XP, 2000, and 98. Everybody on the LAN shares a DSL connection through a router, and all workstations have Norton Internet security either 2002-2004. I have heard that NetBEUI is faster and more efficient than TCP/IP when used in small networks, so I unbounded TCP/IP from File and Printer sharing and Client for Microsoft Networks and only bound NetBEUI. Everything works fine peer-to-peer file sharing, and everybody can still browse the Internet, with the added bonus of more security theoretically (NetBEUI nonroutable). So my question is, I this really a more efficient configuration than just running TCP/IP as the only protocol. Any opinions or suggestions??