Roof Top Cargo Carriers ('06 SE)

[dpiddy]

I'm shopping for a roof top cargo carrier and noticed that most, almost all, say they must be mounted to racks meant to support 150 pounds. I flipped through the manual of my 2006 SE 4Runner and noticed that it's rated for no more than 120 pounds. What gives? I assume this just means that I need to put less cargo in the carrier but that kind of blows. Are there any replacement cross bars that'll take more weight or is it also the roof rack itself at play? The 2006 SE has the metal tubular roof rack with the flattened metal cross bars.

Any first hand experience or tips would be greatly appreciated.

Thanks,
dpiddy