1600 feet is a good distance. I don't think these routers are good unless you can get an antenna outside and in direct line of site between them, then you might be able to use the 5Ghz band using N only. Single mode G 2.4Ghz seems to work the best for doing the distance. Walls and such interfere with this back and attenuate the 5Ghz frequency. I presume your trying to bridge your 655 router to your buddies router using the on board WiFi? Suppose it's too far to bury LAN cable?
BTW, who makes those DS_2400 xcvrs?