I got off the phone with a Dana Spicer engineer and this is what he said about the end forging/yolk/Inner-C and Ultimate Dana 44.
Me: “Just about everyone I talk to recommends welding on Inner-C gussets on Dana 44’s because they bend. And that the Ultimate Dana 44 looks to be the same”
Engineer: "Dana axle end forgings are not the parts that these guys are bending, it's the axle tube, specifically the long side. Anything short of a car wreck is not going to bend the end forgings. These Jeep forums and Internet blogs have been feed a lie from who knows where and are full of BS. Furthermore if you weld on the gussets they sell for the end forgings, your “Inner-C” you'll actually make it weaker because of the heat needed to weld them on changes the grain size, structure and flow imparted by the forging process, so don't do that!”
Me: “What about putting sleeves in mine?”
Engineer: “I’m not in sales and can’t tell you what to buy or do, if done properly installing sleeves will help but it’s a Band-Aid at best, a single thicker tube is far stronger. If you are going to run 35" or 37" tires and actually go off-roading with your JK I would recommend whether or not you buy the Ultimate Dana 44 from us you should upgrade your front axle. Myself and the other Dana Spicer engineer’s specifically designed the Ultimate Dana 44 to address the week axle tubes, brackets and axle shafts among other things on the JK for off-road use with 37” tires. I will tell you we did in fact strengthen the end forgings as well. Above 37” tires I would go with the Dana 60 or the like.”