I have personally never had a problem with ARBs.. but, I have never used one in an app like this... I stick with them for lighter trail toys that see mostly street duty...
For strength, personally, I like the Detroit full carrier locker... nearly indestructable...
I currently have 456 yukons and detroit tru-tracs Love em and wouldnt trade`em for anything!!!!! work great and do really well in my tug-a-trucks dunno about sled pulls as I havent hooked it yet but that time will be here this spring/summer!
it goes by production date, as long as your replacing the set (ring and pinion) not sure why or who would do one you can get the 10.5, iirc. i had a detroit in my 99 f250 with gears from 4 wheel wholesale parts. lifetime warranty on the gears no matter what. an 04 should be 10.5 i think the split is around 99 or 2000