It matters as Ford has obviously chosen to emission and crash test as a light duty truck instead of a heavy light duty truck (6000lb-8500lb is heavy light duty for emissions). They go over and they have to recertify emissions which ain't cheap. For non-emission purposes, 6000lb is where a light truck becomes a heavy duty truck (yep, two different classifications from the same government) and would have to be crashed tested again. Also not exactly cheap. Would Ford make up the difference in profit of roof racks for 4-door 2.7 Sasquatch vehicles? It seems that Ford didn't want to find out. Smart money says they wont be going over 6000lbs on the Bronco GVWR.