The 8.25 will be fine for 35s but if you just have to have a different axle I personally would go with the D44. While the 8.8 is plenty strong I just don't like or trust c-clip axles and for what it cost to get rid of them you could build 2 D44s. Reguardless of which one you built you can still break. I broke shafts in my FFD60 running 35s and have seen it done with 14 bolts as well. It's all in how you ride and how hard you beat on it.

 

the 8.25 is way stronger then people make it. i wouldnt switch it out on 35s, do you daily your rig or is it a trailer queen? this makes a big difference in how you wheel. atleast for me. if this things gotta get me home i wouldnt be as hard on it LOL. the only downside to a 8.25 is c clip.... other then thats its about as stout as a 44. if it was me id just disc brake swap it then your axle cant walk out if you break it. ive done it before i even drove home with a broken axle that way!!

 

I've considered just keeping the 8.25, and can easily get the zj disc parts super cheap. But I want to reliably run 35's with a locker, I like to think I'm nice on the skinny pedal, but I also snow wheel, so I will admit I'm not nice in some scenarios. It's not my main dd, but will need to be driven home from wherever.

I've read with upgraded shafts it's close to d44 strength..