Hyundai/Kia had some cold weather issues blowing hoses and pump seals in cold climates with PSF3.
I would use PSF4 or a full synthetic PSF or ATF.
There is a bulletin allowing the use of any quality PSF in place of PSF3. PSF3 can NOT be used in PSF4 systems. PSF4 can be used in PSF3 systems. Easy OE upgrade!
Mixing is also not recommended. Regardless of what fluid you use, consider a full flush and go from there.
I haven't seen anything 'exotic' in their power steering systems.