Your 327 PC and 327 TRR8 have triggers and hammers that are forged, since they are from the Performance Center. MIM parts are in no way inferior to the older non MIM parts, that perception is a myth.

As for durability, I have a few scandium framed revolvers (three of them) and they have held up just fine to my level of use. IN particular, my 327 M&P R8 (similar to your TRR8) has seen in excess of 6000 rounds in the last 12 months and is running like a top. At one point the barrel nut became loose, and a quick trip back to the factory resolved that.

All of the scandium guns have Smith and Wesson life time warranty, if it breaks send it back! Smith is great about their warranty and I would shoot and carry away with confidence.