They're already top balanced grade A cells versus grade B cells. They're also the cells used in industrial mining, so they're able to tolerate vibration and movement.
> Why buy something that might explode from a trustworthy business, when it's cheaper out the back of some dudes car.
IIRC one of the main advantages of LiFePo4 batteries is that they can't "explode" under the normal circumstances. And if they buy batteries in China anyway, then why not buy from China as well? I'd understand 20-30% premium, but not 200-300%.
Think 'hospital', certified power, military, off-shore (vessels, platforms, emergency power and so on).
For a system that is bullet proof and where there are very strict requirements it makes sense to spend that money, for your homebrew system it likely doesn't, but you can pick up their inverters for a good discount at the various surplus auction sites with some regularity and that's the best of both worlds: great quality at a reasonable price.
> Why buy something that might explode from a trustworthy business, when it's cheaper out the back of some dudes car.