Multiple routers from 1 DSL line?

If you are hard wiring your new WirelessN router into your other router, I would recommend turning off the routing function of one or the other. Turn off NAT, DHCP, DNS, Firewall, everything on one of them. If you have a modem that is a modem/router combo, those are usually pretty crapp and I would recommend disabling that one and making it just a modem and running everything through the new router.