Well I love the XXX-S so far (from a building standpoint, at least) but Losi's packaging department leaves a bit to be desired. The car came without the second male outdrive cup (diff half) and soon after that I realized it only came with 11 of the "heavy duty belleville washers" as opposed to the required 12.
Unfortunately, the only thing that my LHS had that was close to one of those washers was from the Losi regular diff hardware kit (Part #A-3078). The washers in here are the same width, but are just ever-so-slightly thinner than the ones in my kit.
In other words, hopefully putting this sucker in there isn't going to kill anything...
On an unrelated topic (and since I now have enough parts to build a third diff) has anybody experimented with the 41T "option" pulley yet?