A lot of those affect only the jpeg. So if you shoot raw, it might be useless to have them enabled, they will only slow down the processing. Keep in mind also that (especially) the distortion correction can slow down the camera (dunno about the K-3, but it does with previous Pentax cameras) even if you shoot raw, because it is still applied to the preview jpeg files embedded in the raw container (dng or pef).
Highlight correction is the one that affects the raw, since it shoots at lower ISO and digitally brightens the photo without clipping the highlights. So the raw data is actually darker than the preview photograph and it might also affect the brightness curves. Its a bit of a mystery how exactly it works. Some users like this functions, some don't because it limits your selectable ISO range. I like it when shooting on overcast days.
Other than the Peripheral Illumuin. Cor, those features were already available in previous models, so you can find threads about them. (btw, could this be vignetting? or purple fringing?)
tl;dr. If you shoot jpeg and have the time, enable them. If you shoot raw or want fast burst mode, disable them.
Last edited by Na Horuk; 01-07-2014 at 04:46 PM.