I should be on commission for these guys.
I've just uploaded some photos into an album for you to have a closer look at our MM's. I can take some more photos at the weekend if you want some close-ups.
http://picasaweb.google.com/Smokin.Lizard/MetalMules
I reckon the hubbys panniers have done about 12k miles since we bought them and 9k of those, he's fully loaded up. At least a quarter of those miles are off-road on the type of terrain you see in the pics.
Have a look at this site for product testing the exhaust:
http://www.bikehigh.com/prod-tests.html