I am not refering to the physical location of the WBR, I am talking about having 2 routers running right next to each other. Think of it has having two TVs on right next to each other on deifferent channels which one are you going to be able to hear. It's not that the 655 is super sensitive, its part of the IEEE specifications for Wireless N that the N router MUST not interfere with any G or older specs, it will reduce it's Channel Width and thus its overall speed.
Remember on Laptops , they use the cheapest stuff that they can get their hands on. I have taken apart many laptops over the years, and the wire that they use for the antennas has gotten thinner and thinner as the display screens has gotten larger.