The 655 may well be approaching EOL status. I have begun to see the newest .11N routers moving up to the 450 Mbps level for max wireless speeds.
Unless there is some sort of major firmware upgrade that would grant 450 Mbps for the 655, I would suspect DLink will be bringing a new unit to market.....
Considering so many people are still forced to keep their routers to "G & N" because so many devices are locked in to .11G mode (ipod/iphone comes to mind).....who really needs 450 Mbps speeds at this point.