I was doing some thinking between the crew cab's heavier GVW over the ext. cab. The 1500 crew cab has a 7000 GVW. All other 1/2 tons are 6200 or 6400 GVW. What makes it rated higher? Springs? Is the frame bigger? I dont think it has the same frame as the 1500HD. Anybody know why its rated at 7000 lbs ?