I was looking for front diffs for the 8.25 about a year ago, and found the same info already mentioned....the IFS case is too weak to support any type of locker. I did find a company that made a SAS kit using Dodge front axles, as they're also made by AAM and the speed sensors supposedly work fine. Wish I could remember the name of the company though :/
I have True-Tracs front and rear in my K-5 Blazer, and don't remember any problems after initial break-in. I thought they worked rather seamlessly, in fact. Dual steering stabilizers may have helped. Driving on ice was a white-knuckle experience (downright dangerous), but that was probably a function of the mud tires rather than the True-Trac. On anything BUT ice though, the thing was a beast! The K-5 has been sitting in my backyard for the past 10 years or so though awaiting a new motor and tranny, so my recollection might not be the best.....but I didn't regret dual True-Tracs in that thing one bit.