A 30mm versus your 35mm is not a big difference in terms of focal legnth, and will cause some overlap. I would discourage it. If you are happy with your FA35mm f2, why don't you keep it and consider a fast 50mm to complement your 35/2?
There are some great fast fifties for K-mount, including the FA50mm f1.4 (AF), the Sigma 50mm f1.4 (AF), the Zeiss 50m f1.4 (MF), Voigtlander Nokton 58mm f1.4 (MF).
The FA50m f1.4 is well-liked by many Pentaxians and would be nice option to complement your FA35mm f2 if you prefer AF.
Hope that the comments wil help.