Well, I've run about a dozen packs worth through the CRT.5 with the hardened steel pinion and it still seems to be fine. You can see the wear marks, but the overall shape of the teeth are the same.
However, it seems to have developed a wobble, probably because of the 1/8" to 5mm sleeve adaptor. The motor shaft spins perfectly fine by itself. Also, 16T is simply geared too high to continue to use it in this vehicle. So, I'll save it as a spare for my Hyper 8, which is also using a steel spur for testing purposes. I know Mike is working on a plastic spur solution, and so is someone else here, so I think I'll wait until then.