Sure it does. The better the HDMI cable, the more clear and focused the picture will be.
Not true. The picture is digital, pixel-by-pixel. It's not a radio signal. For example, some answers from proper guys here
https://goo.gl/Wx7Skp HDMI doesn't have an error-correction protocol, but you either get a picture as-is or don't get it at all.
For $150 for the iFi SPDIF iPurifier, what do you have to lose? Just return it to Amazon if it doesn't work for you. This will give you a small taste of what a reclocker can do.
Agreed. Waiting for my Chromecast Audio/iPurifier to try.