My LHS didn't have the HPI in stock and they said delivery was "Mid January". with the stock servo saver on their it was in drivable. I'm not exactly sure how i did it but the hex was ever so slighly mangled at the corners of the hex impression. On a wheel hub no big deal, but on a servo saver a fraction of a mm is a deal breaker. When I turned left the steering would not re-center.
Needless to say those first couple laps were a durability test until I figured out what was going on!
Until the HPI horn arrives I've put s Racer's Edge aluminum horn on that I had laying around. The angle on the ball cup is a little troubling, but I don't foresee it being an issue.