Instead of the Kahr PM9... you may want to look into the CM9. You'll save $200-$250 and they are virtually the same other than fancier machining on the slide and polygonal rifling in the barrel. My CM9 is incredibly accurate at it's intended carry range. Smooth as butter trigger is the same on both models as well as the combat sights (very nice too).
Just a thought if price is an issue.
I have a Sig P238 (.380) and love it too... so small and light. Virtually the same as it's 9mm brother. A little pricey... but usually comes with night sights and recoil is minimal for such a small gun due to it's non-polymer design. Built to last.
No experience with Walther pistols... don't do anything for me, so I can't help ya there.