On my old '90 Toyota pickup I replaced the stock wiper blades that came on it with some new ones from Toyota and they were crap. Comparing them the replacements were a harder rubber so I started replacing the whole assembly like you until the parts man was able to start stocking the softer blades and then I was able to only have to change them. They wore out faster, but damn they worked great.I only use the genuine Toyota ones, and one time I tried Toyota blades only, and they made a lot of noise.
What my dealer does is order me the whole assembly with the blade and holder, as it is a different rubber than just the Toyota replacement.
No noises whatsoever.