I just got my Nimbus Meridian, and looking through the manual, I'm really impressed with how many interchangeable parts there are. The narrow shoulder straps seem good enough, but I was thinking about swapping out the ultralight hipbelt for one from their lighweight series of packs.
As it is, there's ample padding, but when I load up the pack, the hipbelt likes to twist. The front of the hipbelt rides up, putting pressure on my stomach instead of my hips. The light hipbelt has some sort of plastic frame, which I'm assuming doesn't weigh too much more.
Has anyone ever made this switch, or used Granite Gear's heavier series of packs for that matter?

