Thank you all for comments.
SSGGeezer - know I understand why my wife is against KP
I am looking yet on additional grips (I have never owned any but it would be nice to try later on...):
- In case of K3 replacements of D-BG5 grips are quite cheap or used one are available too
- for KP only original I see which is quire expensive
Currently in Poland we have prices for cameras (best what I found):
- K3ii 3450 PLN = 935 USD
- KP 3750 PLN = 1015 USD
- k70 2330 PLN - 630 USD
I have to take decision soon - my wife is going to be out of patience (for me)