Feeling accomplished - just installed a set of Trijicon HDs (orange ring) on my PPQ M2 9mm. It took all of 5 minutes with the tools I already had. The front sight screw was finicky, but I managed to finagle it eventually. Compared to the ordeal that changing my Shield sights had been (I ultimately gave up and paid a gunsmith to do it, who charged me $60 for it)... this was a non-issue.
... as if I didn't have enough reasons to love the PPQ.
The sights are pretty awesome. I think I like them better than the TFX PRO I have on the Shield. The front sight is easier to pick up for sure... in almost any light.
I also read a lot about the TP-9 mags being exactly the same as the Walther (for range not carry of course), and I have one of the 18-rounders on order to test that hypothesis.