i am not sure if this is the right forum to ask this but i will any way a salesman told me that if i run my projector through the s video on my hi fi amp it can improve picture quality is this true thanks
First of all, you want to have as few connections between your video source and display device as possible.
That being said, if you want to have the ability to switch video sources through your receiver, you have to look at the specs of your receiver. Some do a better job of "passing the signal along" than others.
At best, there will be very little or noticeable signal degradation. I don't know of any receivers that "enhance" the video signal. Some DVD players and DSS receivers have dual s-video outputs, and you might be able to use both, though I assume your projector only has 1 s-video input.
You are better of just trying it out both ways to see if the difference is noticeable and/or acceptable.