91's are 27 spline. Not the strongest, but better than a d35. Ive been running a detroit, 4.56's and heavy 35's for a while now on the 8.25 with no problems. However i know this is a risky combo and am about half way done with my f&r d60 buildup. Id say go ahead and weld it, and in the mean time, start looking for a cheap 14bolt, or 60 to have on hand once the 8.25 finally calls it quits.
And sorry, but yes it will suck in the snow. Unless you like donuts.... and not the edible ones. Im up in Alaska, where the snow and sub 20* temps last for about half the year. Ive wiped out more times than i can count with that rear locker engaging unexpectedly. At least if you are welded out back, then you will have the advantage of predictability.
