See, the problem I have is that I own the 56 router and paid full retail for it after it first came out along with the dual band asus USB stick to match. That 2TB limit is a hard limit on the 56. And I have had all kinds of trouble with the firmware/admin area, NOT getting dual band performance between the asus stick and the asus router, and drives shared from the router failing to connect to the network (and ponderously slow transfer speeds when it did work). So I need official "it works" before even considering the purchase. Thanks for your reply!
Yes, anything over 2TB is not officially supported, but may still work. It all depends on the model of drive as some have more compatibility issues than others. The RT-N56u is the same as our other routers, you may or may not have luck with your specific larger drives.