load ratings for a jeep

so Have found a great deal on BFG AT k02 but they are only 6 ply rated, the same tire same size in 10 play is about $700 more expensive for a set of 5. My question is is the 6 ply BFG tough enough? especially side wall, What were the old bfs ? 6 or 10 basically the way I understand it is that a 6-py is load rating of C and a 10 ply is an E rated tire.
Should I go e rated or C rated. tire size is 315 70 17. and what is the weight difference ? how much effect will that have?

I am looking to go with a quieter ride. My Kelly safaris TSR howl like a banshee. Dog walking on the side walk snarl and growl at my Jeep. of the 3 tires below if I don't go with BFG which would you go with and why?
The fourth tire is one of my Kelly and all5 are for sale.

most jeeps are light and c rated tire will be fine. In fact might be preferable in most situations. one of the main reasons people go with e rated tires is that in bigger sizes there are not a lot of choices other than e rated. I think it was a wise move on bfg's part to have the ko2 in c rated in the 315/70-17 which I believe is due to ford specifying that for their Raptor.

Most people running E rated tires do it for extra sidewall protection and has nothing to do with load rating. They run 30psi in a tire that takes 80psi. IMO this is not necessary. You'll be perfectly fine with C rated tires and it will ride much nicer. If you are that concerned about tearing open a sidewall pick a different line.