The 6 cylinder looks nice. I would inquire as to what exactly is meant by the "rebuilt rear end" comment. Maybe it has upgraded rear axles... or it could be that it was in a collision and had all that replaced? Definitely work the price down on that.
As far as the yellow one goes, I'm not sure I would want a 4 cyl Auto. Seems like it would be awfully sluggish. But I never test drove one, so I can't say for sure.