We looked at those. It didnt appear on the surface to be worth the increase in price. Looks like that is for 8 cells only. So youd need more than that. Crating appears to be 2.5c which is common. Higher is better. I *heard* the k2s are 10c, which makes sense. Our 90/100ah is only about as strong as their 40ah or whatever size that is.
If anyone wants a cheap project, try Tenergy cells. They are a nice option because tenergy actually makes charges for their cells. The charger works great and is only like 40$