If you wash them enough, the seats stop staining. I don't have that much dedication, so half of my front passenger seat is all that won't stain.
Honestly it wasn't too bad to do, but it was summer (too damn hot to sit out there scrubbing seats) and I'm probably going to switch to the Katzkin leather eventually.
As for the headrests, yeah, they pop right off. On the one shaft is the adjuster button, on the other shaft is a recessed button for the headrest retainer. Put the headrest up all the way, then press in on the recessed button (your keys work well) and pull up on the headrest. Try not to hit the headliner when it comes out.
You'll probably need to either recline the seat or put it down all the way. Maybe both if you've got the sunroof.