the thing that makes me LOL about hard cases is that they have a crack around the outside to show you that the pack has puffed up if it does the pack is no longer roar aproved, becuase they put the sticker right over that part also hardcases really aren't gunna provide any more protection because the cases are made of just ABS or a similar plastic, and personally i don't think that will absorb much shock from a loose battery, in my opinion the best way to protect any battery is keep it still if this means putting bits of foam around it do so, and a soft case should just be fine, personally unless i can get hardcases for about the same price and they'll fit fine, then i'm gunna go for them just because of the small chance of external dammage IE flying rocks... but if they're not i have no issue running a soft case...

the lug