Everything matter in the audio chain. Tests prove it!

Everything matters even more if it isn't plugged in. Yah, some of my customers were concerned about a unit that I sold many of, not working. To cut to the chase, I quit putting the power button on the rear of the unit just for that reason.

  Of course everything counts, it is just a matter of to what degree. One exception would be that if a cable or component had an issue in the first place and you replace it with something working properly, then no doubt you will hear an improvement. 

 That is a coarse way of stating that everything does matter but to varying degrees.

@teo_audio 

the differences will be notably more huge, if one does transient and complex transients stacked and their harmonics, as a fundamental test.

I take it you must know of tests that have already shown this?

@brauser

I recently experimented with a SOTA power cable from Audio Magic replacing the stock cable and the improvement in picture quality was dramatic.

What kind of image quality improvements did you see? Are they obvious enough that you could take before and after pictures of the screen to demonstrate the difference? On my equipment I have seen the image quality occasionally go weird and had I taken a picture of it I'm sure I could have demonstrated it. In those cases I had to restart or reconnect something to get the picture back to it's normal excellence. 

I have used the Blu-ray version of Avatar as a reference disc to test the would-be improvements to the video side of our home theater. One of the scenes is when the helicopter is making a landing at a remote location. The grass is being blown and the whole area has a lot of movement. The increase in detail and coloration is stunning. I am using the Sony VPL-VW325ES 4K LCOS Projector and high-quality interconnects, screen etc.

My guess is that the power cord to the projector is one of the last things that people think about when trying to upgrade the picture. It sure has made a big difference in our system.