I also got a chance to do some practice running with my DI today at SRS (where they run the Cactus Classic) and the buggy did pretty good. I'm running the B4 shocks on mine and they work well. The rear springs I have on it are too stiff so the back end wanted to bounce up a bit more than it should. I'll correct that next time out. The track was pretty loose (not watered) and the back end kicked out in the loose stuff. I will probably add a little weight to the rear and the lighter rear springs may help this too.
As far as durability, I am a relatively new racer so I hit things more often than I should. So far the DI has held up with no broken parts. I've landed it square on the nose and smacked it sideways into brick walls with no damage so far. I have landed it upside down on the front tower with no cracking yet. I do have a spare just in case.
I really hope they get the one-way diff soon. It would really enhance this buggy. There were some turns that the buggy got sliding sideways, because the front end was still coupled to the rear, that would have been tamed by a free-wheeling front end.