If you are using it where other ambient or artificial light is present then it will sometimes look noticeably pink. If its outside at night you will not notice at all. Comparing it to other LEDs side by side is the most pink it will ever look though so every other situation will look more natural
The sw45k is a very special LED, you will not be disappointed. It would be hard for me to choose between the sw40 and the sw45k if I could only have one, but I think it would be the sw45k.
I do not notice that the sw45k is pinkish when used by itself. It just has a great tint. But when compared to other LEDs, like the Samsung LH351D or Luminus SST-20, the rosiness proudly comes out and makes the others look greenish.