S-Video should be better than your standard Yellow Composite cable, but not as good as an Component. I can't see why you couldn't mix and match Component Cables. Maybe you'd want to check an alternative source, but they're transmitting a very similar signal, so I'd assume the build would be the same.
When you can, go with HDMI, but obviously you can't with the Tivo.
This is a little dated, but it should help to clarify some things:
http://www.lyberty.com/encyc/articles/svideo.html